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COVID-19 vaccines have been illustrated to lessen the growth of sickness caused by the virus effectively. In any case, inoculation has consistently been controversial, with differing opinions and viewpoints. This has compelled some individuals to decide against receiving the vaccine. These divergent viewpoints have had a trivial impact on the epidemic's dynamics and the disease's development. In response to vaccinated individuals still falling ill, many countries have implemented booster vaccines to protect further. In this specific investigation, a mathematical model composed of seven compartments is employed to examine the effectiveness of a booster dose in preventing and treating the transmission of COVID-19. The principles of mathematics are employed to analyse and investigate the dynamics of the disease. Using a qualitative prototype analysis, we acquired valuable insights into its effectiveness. One essential aspect is the basic reproduction number, a critical determinant of the disease's spread. This calculation is determined by studying the system's equilibrium and evaluating its stability. Furthermore, we examined the balance from a local and global viewpoint, considering the possibility of bifurcation and the model's reproductive number sensitivity index. Through numerical simulations, we have visually illustrated the analytical findings outlined in this research paper and presented a thorough examination of the efficacy of booster shots as a preventive and therapeutic measure in the spread dynamics of COVID-19., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Test-negative designs (TNDs) are used to assess vaccine effectiveness (VE). Protection from infection-induced immunity may confound the association between case and vaccination status, but collecting reliable infection history can be challenging. If vaccinated individuals have less infection-induced protection than unvaccinated individuals, failure to account for infection history could underestimate VE, though the bias is not well understood. We simulated individual-level SARS-CoV-2 infection and COVID-19 vaccination histories and a TND. VE against symptomatic infection and VE against severe disease estimates unadjusted for infection history underestimated VE compared to estimates adjusted for infection history, and unadjusted estimates were more likely to be below 0%, which could lead to an incorrect interpretation that COVID-19 vaccines are harmful. TNDs assessing VE immediately following vaccine rollout introduced the largest bias and potential for negative VE against symptomatic infection. Despite the potential for bias, VE estimates from TNDs without prior infection information are useful because underestimation is rarely more than 8 percentage points., Competing Interests: Competing interests: The authors declare that they do not have any commercial or other associations that might pose a conflict of interest., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

The mucosal immune response plays a crucial role in the prevention of respiratory viruses. Given the risk of recurrent SARS-CoV-2 infections in the population, the rapid development of next-generation intranasal COVID-19 vaccines with high safety and efficacy is paramount. In the current study, we developed a protein-based intranasal vaccine comprising the XBB.1.5 receptor binding domain (RBD)-derived trimeric recombinant protein (RBD XBB.1.5 -HR) and an MF59-like oil-in-water adjuvant. Intranasal administration of RBD XBB.1.5 -HR vaccine elicited robust and sustained humoral immune responses in mice and rats, resulting in high levels of neutralizing antibodies against XBB-lineage subvariants, with protection lasting for at least six months. The intranasal RBD XBB.1.5 -HR vaccine generated potent mucosal immune responses, characterized by the inductions of tissue-resident T (T RM ) cells, local cellular immunity, germinal center, and memory B cell responses in the respiratory tract. The combination of intramuscular and intranasal delivery of the RBD XBB.1.5 -HR vaccine demonstrated exceptional systemic and mucosal protective immunity. Furthermore, intranasal delivery of RBD XBB.1.5 -HR vaccine as a heterologous booster shot showed more effective boosting effects after mRNA administration compared to homologous vaccination, as evidenced by the induction of superior systemic and extra mucosal immune response. Importantly, the intranasal RBD XBB.1.5 -HR vaccine conferred efficient protection against the challenge with authentic EG.5.1 viruses in vivo. These findings identify the intranasal RBD XBB.1.5 -HR vaccine as a potential mucosal vaccine candidate for the prevention of SARS-CoV-2 infection., Competing Interests: Competing interests This work was supported by the WestVac Biopharma Co. Ltd. Jingyun Yang, Jiong Li, L.Y., Z.W., W.W., G.S., Jinliang Yang, Z.Z., G.L., and X.W. are also working at the WestVac Biopharma Co. Ltd. The remaining authors declare no competing interests., (© 2024. The Author(s).)

Objective: The objective is to externally validate and assess the opportunity to update the Canadian COVID-19 Mortality Score (CCMS) to predict in-hospital mortality among consecutive non-palliative COVID-19 patients infected with Omicron subvariants at a time when vaccinations were widespread., Design: This observational study validated the CCMS in an external cohort at a time when Omicron variants were dominant. We assessed the potential to update the rule and improve its performance by recalibrating and adding vaccination status in a subset of patients from provinces with access to vaccination data and created the adjusted CCMS (CCMS adj ). We followed discharged patients for 30 days after their index emergency department visit or for their entire hospital stay if admitted., Setting: External validation cohort for CCMS: 36 hospitals participating in the Canadian COVID-19 Emergency Department Rapid Response Network (CCEDRRN). Update cohort for CCMS adj : 14 hospitals in CCEDRRN in provinces with vaccination data., Participants: Consecutive non-palliative COVID-19 patients presenting to emergency departments., Main Outcome Measures: In-hospital mortality., Results: Of 39 682 eligible patients, 1654 (4.2%) patients died. The CCMS included age, sex, residence type, arrival mode, chest pain, severe liver disease, respiratory rate and level of respiratory support and predicted in-hospital mortality with an area under the curve (AUC) of 0.88 (95% CI 0.87 to 0.88) in external validation. Updating the rule by recalibrating and adding vaccination status to create the CCMS adj changed the weights for age, respiratory status and homelessness, but only marginally improved its performance, while vaccination status did not. The CCMS adj had an AUC of 0.91 (95% CI 0.89 to 0.92) in validation. CCMS adj scores of <10 categorised patients as low risk with an in-hospital mortality of <1.6%. A score>15 had observed mortality of >56.8%., Conclusions: The CCMS remained highly accurate in predicting mortality from Omicron and improved marginally through recalibration. Adding vaccination status did not improve the performance. The CCMS can be used to inform patient prognosis, goals of care conversations and guide clinical decision-making for emergency department patients with COVID-19., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: COVID-19 vaccination rates remain low for children aged 11 and below, and understanding the extent to which parental decisions impact their children's vaccination status remains a challenge. This study aimed to explore the concordance and motivations for vaccination among parent-child dyads and determine the associated factors influencing their children's vaccination status., Design: A cross-sectional study was conducted from 1 March 2023 to 30 March 2023, recruiting parents from six representative primary schools across Butuan City, the Philippines. Pilot-tested, self-administered questionnaires were used during the face-to-face surveys with parent participants. To determine the associated factors of parental decisions to vaccinate their children, mixed-effects logistic regression was used, with school districts as a random effect., Participants: A total of 593 participating parents were included in the study, with the majority being females (n=484, 81.6%) and underserved, characterised by lacking a college degree (n=305, 51.4%) and having low to no income (n=511, 86.1%)., Results: While 80.6% (n=478) of parents reported being vaccinated against COVID-19, only 36.2% (n=215) of them chose to vaccinate their children. A significant number of parents (n=285, 48.1%) reported psychological distress, with higher levels of distress prevalent among those who are indigenous, reside in rural areas and have lower income levels. Parental education and vaccination status emerged as influential factors. Specifically, parents with advanced degrees were 48% less likely to have unvaccinated children (adj OR (AOR)=0.52; 95% CI 0.30, 0.87), while unvaccinated parents had a sixfold increase in the likelihood of having unvaccinated children (AOR 6.1; 95% CI 3.14, 12.02) compared with their counterparts., Conclusions: Efforts to increase paediatric vaccination rates should focus more on actively engaging parents, educating them about the vaccine's benefits and necessity, rather than solely relying on mandates to improve paediatric vaccination rates. Further research is needed to understand the reluctance of unvaccinated parents to vaccinate themselves and their children against COVID-19, identifying specific facilitators and barriers to develop more effective communication strategies and bolster vaccine acceptance., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Studies predating widespread COVID-19 vaccination identified patients with congenital heart disease (CHD) as a group at increased risk of severe outcomes from COVID-19. Here we evaluate the impact of vaccination on COVID-19 outcomes among patients with CHD., Methods: We conducted a case-control study using linked English electronic health records (n=3 18 135). Patients with CHD were matched with controls by age, sex, ethnicity and GP practice. The 'prevaccination' cohort comprised unvaccinated patients with CHD and matched controls with first-recorded SARS-CoV-2 infection between 1 March and 8 December 2020 (7805 cases, 27 620 controls). The 'post-vaccination' cohort comprised vaccinated patients with CHD and matched controls with first-recorded SARS-CoV-2 infection between 1 March 2021 and 1 April 2022, at least 14 days after vaccination (57 550 cases, 225 160 controls). Odds of severe COVID-19 outcomes were compared using conditional logistic regression. We also compared the rate at which vaccine efficacy diminished, and the incidence of vaccine-associated complications., Results: Compared with the prevaccination cohort, postvaccination patients with CHD exhibited markedly reduced rates of COVID-19-related hospitalisation (0.5% vs 15.8%) and mortality rates (0.5% vs 4.6%). Compared with vaccinated controls, vaccinated patients with CHD remained at increased risk of hospitalisation (0.5% vs 0.2%, adjusted OR 2.24 (1.88-2.65); p<0.001) and death (0.5% vs 0.3%, adjusted OR 1.81 (1.54-2.13); p<0.001). There was no evidence that vaccine efficacy declined faster in patients with CHD, or that patients with CHD experienced a larger increase in incidence of myocarditis, pericarditis or thrombotic events., Conclusion: We observed a lower absolute risk of hospitalisation and death from COVID-19 in CHD patients after vaccination. However, in vaccinated CHD patients, an elevated risk of severe outcomes persists compared with vaccinated people without CHD. These results emphasise the importance of vaccination in the CHD population, and of vigilance among care providers dealing with COVID-19 infection in CHD patients, even if fully vaccinated., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Administration of coronavirus disease-2019 (COVID-19) vaccines with appropriate booster doses through painful injections under clinical supervision was challenging during the recent COVID-19 pandemic. As an alternative solution, we designed a safer, edible probiotic yogurt vaccine prototype (YoVac) that can be orally consumed by circumventing painful injections and clinical supervision. We hypothesized that YoVac prepared using Lactobacillus carrying an antigen coding gene (donor) can transfer the same to other bacteria (recipients) in the human gut microbiome (hgMb) through lateral gene transfer (LGT) for boosted antigen levels potentially triggering a robust immune response. In this study we confirmed the in vitro LGT efficiency of a plasmid (pRBD-Amp r ) containing severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) spike protein-receptor binding domain (RBD) coding gene along with an ampicillin-resistance gene (selection marker) from the probiotic Lactobacillus (donor) cultured from homemade yogurt to E. coli and Helicobacter pylori (recipients). Both the donor and recipient bacteria not only exhibited ampicillin-resistance from pRBD-Amp r but also expressed RBD protein. Furthermore, Lactobacillus isolated from YoVac consistently showed the expression of RBD protein over a period of one month confirming the shelf life of our prototype stored at 4 °C. Taken together, our in vitro results provide a preliminary basis for the potential in vivo transfer of RBD coding gene from YoVac to other bacterial species in the hgMb through LGT and may potentially boost the vaccine dosage by delegating them., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: The COVID-19 pandemic has underscored the need for increased vaccine availability and uptake, with vaccine hesitancy posing a significant barrier, particularly among young adults. Evidence from various countries highlight high levels of hesitancy among young people, necessitating targeted interventions. Engaging young adults as key stakeholders in shaping public health strategies is crucial, as their perspectives can enhance vaccine acceptance. This study aimed to assess the overall acceptability of the COVID-19 vaccine among young people and to explore the factors influencing their willingness or reluctance to be vaccinated now and in the future., Methods: This study used qualitative data from 165 young adults in Nigeria, South Africa, and Zambia, to explore their suggestions for policies and strategies aimed at enhancing the acceptance of the Covid-19 vaccination among their age group. Data collection involved focus groups and interviews that explored participants' perceptions and recommendations regarding COVID-19 vaccination acceptability. Thematic analysis was used to analyse the data., Results: Thematic analysis identified several factors influencing vaccine acceptability among young people and suggested recommendations to improve it. The themes included developing targeted communication strategies for accurate vaccine information, offering alternative vaccination methods, promoting vaccine education in schools, and using trusted public figures to share accurate information., Conclusions: Persistent dissatisfaction with vaccine information dissemination underscores the need for more targeted communication strategies among young adults. Recommendations include developing non-injection vaccine options, incorporating vaccine education into school curricula and community programs, and leveraging influential public figures to build credibility. These insights are valuable for designing future programs to enhance vaccine acceptance among adolescents., Competing Interests: Declarations Ethics approval and consent to participate Ethical approval for this study was obtained from the Biomedical Research Ethics Committee of the University of the Western Cape (BM21/10/39). The research was conducted in accordance with the Declaration of Helsinki. We obtained written consent from all participants, with additional consent obtained from parents or guardians for participants under 18 years of age. Consent forms were translated into the relevant local languages and explained verbally to participants. As a token of appreciation for their involvement in the research, IDI participants received airtime compensation, while the FGD participants were provided with snacks and a hot meal and reimbursed for their transport expenses. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Since the beginning of mass vaccination campaign for COVID-19 in Italy (December 2020) and following the rapidly increasing vaccine administration, sex differences have been emphasized. Nevertheless, incomplete and frequently incoherent sex-disaggregated data for COVID-19 vaccinations are currently available, and vaccines clinical studies generally do not include sex-specific analyses for safety and efficacy. We looked at sex variations in the COVID-19 vaccine's effectiveness against infection and severe disease outcomes. We conducted a nationwide retrospective cohort study on Italian population, linking information on COVID-19 vaccine administrations obtained through the Italian National Vaccination Registry, with the COVID-19 integrated surveillance system, held by the Istituto Superiore di Sanità. The results showed that, in all age groups, vaccine effectiveness (VE) was higher in the time-interval ≤120 days post-vaccination. In terms of the sex difference in vaccination effectiveness, men and women were protected against serious illness by vaccination in a comparable way, while men were protected against infection to a somewhat greater extent than women. To fully understand the mechanisms underlying the sex difference in vaccine response and its consequences for vaccine effectiveness and development, further research is required. The sex-related analysis of vaccine response may contribute to adjust vaccination strategies, improving overall public health programmes.

Messenger RNA (mRNA) vaccines are a key technology in combating existing and emerging infectious diseases. However, improving the immunogenicity and durability of mRNA vaccines remains a challenge. To elicit optimal immune responses, integrating antigen-encoded mRNA and immunostimulatory adjuvants into a single formulation is a promising approach to enhancing the efficacy of mRNA vaccines. Here, we report an adjuvant strategy to enhance the efficacy of mRNA vaccines by co-loading mRNA encoding the antigen (rabies virus glycoprotein, RABV-G) and mRNA encoding IL-7 into lipid nanoparticles, achieving co-delivery to the same antigen-presenting cells. A single immunization with G&IL-7 mRNA vaccine elicited robust humoral immune responses in mice and conferred complete protection against RABV challenge. Notably, the high levels of neutralizing antibody induced by the G&IL-7 mRNA vaccine were maintained for at least 6 months, providing mice with long-term significant and complete protection against RABV. Additionally, IL-7 also enhanced antibody responses against the SARS-CoV-2. These data demonstrate that IL-7 is a potent mRNA vaccine adjuvant that can provide the required immune stimulation in various mRNA vaccine formulations., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

In this prospective longitudinal study, we evaluated the durability of humoral responses to SARS-CoV-2 mRNA booster vaccination in 93 people with HIV, exploring the possible role of T-cell dysfunction and inflammaging biomarkers in predicting antibody waning. We found that, despite a negligible influence of the inflammaging milieu, low CD4/CD8 ratio and CD4+CD127+ percentage as well as high CD8+CD38+CD45RO+ percentage are associated with faster antibody waning, in turn contributing to our understanding of the determinants of COVID-19 vaccine-elicited immune response in this population., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Little is known about rates of COVID-19 vaccine uptake among youth with bipolar spectrum disorders (BSD). As such, the aim of this study is to assess rates and predictors of COVID-19 vaccine uptake among youth with BSD and their caregivers in the United States., Methods: Youth and their main caregiver were recruited from a large pragmatic study cohort. Youth who were aged 8-22 at the time of this data collection, had a bipolar-spectrum disorder diagnosis, had overweight or obesity, and were treated with a second-generation antipsychotic were invited to participate in an online survey and interview assessing the impact of the COVID-19 pandemic., Results: A total of 453 surveys and 341 interviews were completed 07/2021-05/2022 by youth and their caregivers. Sixty-seven percent of caregivers and 63 % of youth reported receiving the COVID-19 vaccine. Vaccine uptake rates among youth and caregivers were highly correlated. Predictors of vaccine uptake among youth were older age and living in the Northeast Region of the United States. Predictors of caregiver vaccine uptake were male sex, higher annual household income and not having to quarantine due to COVID-19., Limitations: The sample was small and not a full representation of a population with bipolar-spectrum disorders therefore, the results may not be generalizable. The study design and statistical method do not allow for causal inferences to be made., Conclusions: These findings may aid in targeting interventions to maximize COVID-19 and other vaccine uptake in youth with bipolar disorders and their families., Competing Interests: Declaration of competing interest Author Disclosures: Dr. DelBello has received research support from Allergan, Alkermes, Janssen, Johnson and Johnson, Lundbeck, Myriad, NIMH, Otsuka, PCORI, Pfizer, Shire, and Sunovion. She has received consulting/advisory/board/honoraria support from Alkermes, CMEology, Johnson and Johnson, Medscape, Myriad, and Sage. Dr. Correll has been a consultant and/or advisor to or has received honoraria from: AbbVie, Acadia, Adock Ingram, Alkermes, Allergan, Angelini, Aristo, Biogen, Boehringer-Ingelheim, Bristol-Meyers Squibb, Car dio Diagnostics, Cerevel, CNX Therapeutics, Compass Pathways, Darnitsa, Delpor, Denovo, Gedeon Richter, Hikma, Holmusk, IntraCellular Therapies, Jamjoom Pharma, Janssen/J&J, Karuna, LB Pharma, Lundbeck, MedAvante-ProPhase, MedInCell, Merck, Mindpax, Mitsubishi Tanabe Pharma, Mylan, Neurocrine, Neurelis, Newron, Noven, Novo Nordisk, Otsuka, Pharmabrain, PPD Biotech, Recordati, Relmada, Reviva, Rovi, Sage, Seqirus, SK Life Science, Sumitomo Pharma America, Sunovion, Sun Pharma, Supernus, Tabuk, Takeda, Teva, Tolmar, Vertex, and Viatris. He provided expert testimony for Janssen and Otsuka. He served on a Data Safety Monitoring Board for Compass Pathways, Denovo, Lundbeck, Relmada, Reviva, Rovi, Supernus, and Teva. He has received grant support from Janssen,Takeda and PCORI. He received royalties from UpToDate and is also a stock option holder of Cardio Diagnostics, Kuleon Biosciences, LB Pharma, Mindpax, and Quantic. Dr. Patino has received research support from NIMH, PCORI, Acadia, Alkermes, Allergan, Janssen, Johnson and Johnson, Lundbeck, Myriad, Otsuka, Pfizer, Sunovion, and Shire. Drs. Klein, Welge, Fornari, and Higdon and Mr. Blom received salary support from PCORI. Ms. Keller and Ms. Wingler declare they have no financial interests. This study was funded by: PCORI Award Number: PCS-1406-19276., (Published by Elsevier B.V.)

Background: Pneumococcal carriage is associated with increased acquisition and duration of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among adults. While pneumococcal conjugate vaccines (PCVs) prevent carriage of vaccine-serotype pneumococci, their potential impact on coronavirus disease 2019 (COVID-19)-related outcomes remains poorly understood in populations with prevalent immunity against SARS-CoV-2., Methods: We undertook a retrospective cohort study of adults aged ≥65 years in the Kaiser Permanente Southern California healthcare system who had received ≥2 COVID-19 vaccine doses, comparing risk of SARS-CoV-2 infection between 1 January 2021 and 31 December 2022 among recipients and nonrecipients of 13-valent PCV (PCV13) employing multiple strategies to mitigate bias from differential test-seeking behavior., Results: The ajusted hazard ratio of confirmed SARS-CoV-2 infection comparing PCV13 recipients to nonrecipients was 0.92 (95% confidence interval [CI], .90-.95), corresponding to prevention of 3.9 (95% CI, 2.6-5.3) infections per 100 person-years. Following receipt of 2, 3, and ≥4 COVID-19 vaccine doses, aHRs (95% CI) were 0.85 (.81-.89), 0.94 (.90-.97), and 0.99 (.93-1.04), respectively. The aHR (95% CI) for persons who had not received COVID-19 vaccination in the preceding 6 months was 0.90 (.86-.93), versus 0.94 (.91-.98) within 6 months after COVID-19 vaccination. Similarly, aHRs (95% CI) were 0.92 (.89-.94) for persons without history of documented SARS-CoV-2 infection, versus 1.00 (.90-1.12) for persons with documented prior infection., Conclusions: Among older adults who had received ≥2 COVID-19 vaccine doses, PCV13 was associated with modest protection against SARS-CoV-2 infection. Protective effects of PCV13 were greater among individuals expected to have weaker immune protection against SARS-CoV-2 infection., Competing Interests: Potential conflicts of interest. J. A. L. discloses receipt of research grants and consulting honoraria from Pfizer and Merck, Sharp & Dohme and consulting honoraria from Seqirus and VaxCyte, all unrelated to this research. S. Y. T. reports receipt of research grants related and unrelated to this research from Pfizer. L. R. G., A. A., A. C., L. J., and B. D. G. are employees of Pfizer and may hold stocks or stock options. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: In response to the challenge of maintaining COVID-19 vaccination coverage amidst the pandemic, VillageReach, in collaboration with the Ministry of Public Health Prevention and Hygiene in Kinshasa, DRC, integrated COVID-19 vaccination with routine immunization services at two primary healthcare facilities. This initiative, launched in July 2022, represented the first of its kind in the DRC, aiming to assess the effectiveness and scalability of a multimodal vaccination approach., Methods: Through a rapid appraisal involving key informant interviews and analysis of pre- and post-integration service delivery data, this case study explores the operational dynamics and outcomes of integrating COVID-19 and routine immunizations., Results: Results demonstrated that the integrated approach not only maintained COVID-19 vaccine coverage but also significantly enhanced routine immunization uptake, particularly among under-immunized and zero-dose children. Overall, the vaccination sites, outreach, and integrated health facilities administered 229,983 (33 %) of COVID-19 vaccines in Kinshasa, of which 53 % were referred by community health workers. Additionally, 998 under-immunized children received routine immunizations, of whom 126 were zero-dose children. Key success factors included sustained community health worker engagement, neighborhood-specific strategies, accessible vaccination points, and robust data management. The findings suggest that such integrative strategies can effectively bolster immunization coverage in urban poor communities, offering valuable insights for similar initiatives in the DRC and beyond., Conclusion: This study advocates for sustained investment in innovative immunization models to strengthen primary healthcare systems post-pandemic., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare no conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: BBV152 (Covaxin™) is a whole-virion inactivated SARS-CoV-2 vaccine mixed with an immune adjuvant. We aimed to compare immune responses after booster vaccination with heterologous BBV152 versus homologous mRNA vaccine., Methods: We conducted a randomized, participant-blinded, controlled trial. Fifty mRNA-vaccinated participants were enrolled and randomized to receive an mRNA booster (n = 26) or BBV152 (n = 24). Blood samples were collected pre-vaccination, and at Day 7, 28, 180 and 360 post-booster for analysis of humoral and cellular immune responses. Primary end point was the SARS-CoV-2 anti-spike antibody titer at day 28., Results: Recruitment began in January 2022 and was terminated early due to the BBV152 group meeting pre-specified criteria for futility. At Day 28 post-boost, mean SARS-CoV-2 spike antibody titers were lower with BBV152 (2004 IU/mL; 95 % confidence interval [CI], 1132-3548) vs mRNA (26,669 IU/mL; 95 % CI, 21,330-33,266; p < 0.0001), but comparable levels of spike-specific CD4 and cytotoxic T-cells were observed. Anti-spike antibody titers remained significantly different at Day 180: BBV152 4467 IU/mL (95 % CI, 1959-10,186) vs mRNA 20,749 IU/mL (95 % CI, 12,303-35,075; p = 0.0017). Levels of surrogate virus neutralizing antibodies against ancestral and Omicron subvariants BA.1 and BA.2 were significantly higher among mRNA recipients at Day 180, including after adjusting for intercurrent infection. By Day 360, anti-spike antibody titers and neutralizing antibody levels against Omicron subvariants became similar between vaccine groups. By the end of the study, 16 in each arm (mRNA 64 % and BBV152 69.6 %) had breakthrough infections and time to COVID-19 infection between vaccine groups were similar (p = 0.63)., Conclusions: Wild-type SARS-CoV-2 anti-spike antibody titer and surrogate virus neutralizing test levels against wild-type SARS-CoV-2 and Omicron subvariants BA.1/BA.2/BA.5 were significantly higher at Day 28 and 180 in individuals who received booster vaccination with an mRNA vaccine compared with BBV152., Clinical Trial Registration Number: NCT05142319., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Anti-SARS-CoV-2 vaccination has saved millions of lives in the past few years. To maintain a high level of protection, particularly in at-risk populations, booster doses are recommended to counter the waning of circulating antibody levels over time and the continuous emergence of immune escape variants of concern (VOCs). As anti-spike serology is now widely available, it may be considered a useful tool to identify individuals needing an additional vaccine dose, i.e., to screen certain populations to identify those whose plasma antibody levels are too low to provide protection. However, no recommendations are currently available on this topic. We reviewed the relevant supporting and opposing arguments, including areas of uncertainty, and concluded that in most populations, spike serology should not be used to decide about the administration of a booster dose. The main counterarguments are as follows: correlates of protection are imperfectly characterised, essentially owing to the emergence of VOCs; spike serology has an intrinsic inability to comprehensively reflect the whole immune memory; and booster vaccines are now VOC-adapted, while the commonly available commercial serological assays explore antibodies against the original virus., Competing Interests: Declaration of competing interest Anna L. Goodman reports grants from Novavax to run vaccine trials and non-commercial funding from the INSIGHT network (NIH-TICO trial) to her institution outside of the submitted work; moreover, ALG is named on a patent AstraZeneca vaccine issued to the University of Oxford and has received personal financial contributions for this. Manuel Krone received honoraria from Abbott, GSK and Pfizer outside this work. All other authors have not conflict of interest to declare., (Copyright © 2024. Published by Elsevier Ltd.)

Background: To overcome supply issues of COVID-19 vaccines, this partially single blind, multi-centric, vaccine trial aimed to evaluate humoral immunogenicity using lower vaccine doses, intradermal vaccination, and heterologous vaccine schedules. Also, the immunity after a booster vaccination was assessed., Methodology: 566 COVID-19-naïve healthy adults were randomized to 1 of 8 treatment arms consisting of combinations of BNT162b2, mRNA-1273, and ChAdOx1-S. Anti-Receptor-Binding Domain immunoglobulin G (RBD IgG) titers, neutralizing antibody titres, and avidity of the anti-RBD IgGs was assessed up to 1 year after study start., Results: Prolonging the interval between vaccinations from 28 to 84 days and the use of a heterologous BNT162b2 + mRNA-1273 vaccination schedule led to a non-inferior immune response, compared to the reference schedule. A low dose of mRNA-1273 was sufficient to induce non-inferior immunity. Non-inferiority could not be demonstrated for intradermal vaccination. For all adapted vaccination schedules, anti-RBD IgG titres measured after a first booster vaccination were non-inferior to their reference schedule., Conclusion: This study suggests that reference vaccine schedules can be adapted without jeopardizing the development of an adequate immune response. Immunity after a booster vaccination did not depend on the dose or brand of the booster vaccine, which is relevant for future booster campaigns. The trial is registered in the European Union Clinical Trials Register (number 2021-001993-52) and on clinicaltrials.gov (NCT06189040)., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Pierre Van Damme reports financial support was provided by Belgian Health Care Knowledge Centre. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper]., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Undervaccination and vaccination-related anxieties among marginalised communities like the transgender and gender-diverse (TGD) and disability communities are underexplored in the Indian context. Our study seeks to understand the role of structural and historical inequities in shaping COVID-19 vaccine access for the two communities in India., Methods: Using a participatory qualitative research approach, TGD and disabled individuals were involved in and consulted throughout the research process. We interviewed 45 individuals for our study, hailing from the two communities and other key stakeholders and health system representatives involved in vaccination roll-out in India. We conducted an inductive thematic analysis guided by the socio-ecological model and intersectionality approach., Results: Despite intent to get vaccinated among most participants, several structural barriers shaped COVID-19 vaccine access for people from the TGD and disability community. This included information and communication gaps with respect to the specific health needs of the two communities, barriers related to vaccine registration, data collection, transport, infrastructure and actual or anticipated mistreatment at vaccine centres. Each emergent structural gap in vaccination had parallels in past health systems experiences, pointing to the longstanding and pervasive inequities within health and allied systems which impact how communities perceive and respond to new health system interventions., Conclusion: This study uncovers the structural inequities within health systems that have permeated the planning, design and outreach of COVID-19 vaccination programs in India. Moving beyond notions of vaccine hesitancy among the TGD and disability community, we underscore the importance of socio-historical contexts of marginalisation and advocate for systems to recognise these contexts and respond equitably to the vaccination and health needs of the two communities. While some challenges among the two communities were distinct, the study explores how a shared experience of exclusion from public systems can provide avenues for cross-movement advocacy and solidarity, and help inform health system reforms., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Suspected allergic reactions after mRNA COVID-19 vaccination withheld multiple individuals from getting fully vaccinated during the pandemic. We vaccinated adults who had experienced possible allergic symptoms after their first intramuscular dose of a COVID-19 mRNA vaccine with a 1/5th fractional intradermal test dose of the mRNA-1273 (Moderna) COVID-19 vaccine. No anaphylactic reactions were observed after intradermal vaccination (n = 56). Serum anti-S1 IgG concentrations were measured using a bead-based multiplex assay four weeks after vaccinations. Antibody concentrations were compared with a previously collected nationwide cohort that had received two intramuscular doses of mRNA-1273. Antibody responses in all subjects tested (n = 47) were comparable to standard of care intramuscular dosing. Fractional intradermal dosing of mRNA COVID-19 vaccines may provide a pragmatic solution that is safe, time efficient compared to skin prick testing, dose sparing and immunogenic in individuals with suspected vaccine allergy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a newly recognized syndrome mediated by anti-platelet factor 4 antibodies induced by Covid-19 adenovirus-vectored vaccines including ChAdOx1 nCoV-19 and Ad26.COV2.S. This study validated a proposed Brighton Collaboration case definition for VITT. A data collection form was developed and used to capture the variations in VITT criteria and assess their level of diagnostic certainty from adjudicated positive VITT case datasheets in Germany (n = 71), UK (n = 220), Australia (n = 203), and Taiwan (n = 56). We observed high prevalence of each component of the proposed VITT definition in positive cases (84%-100%), except for the occurrence of thrombosis or thromboembolism criterion in only 34% of VITT cases in Taiwan. The sensitivity of this proposed definition was 100% for Germany and UK, 92% for Australia, and 89% for Taiwan cases. These findings support the validity of this case definition for VITT., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: H. Tran reports project grant funding support outside of the submitted work from AstraZeneca and Sanofi. W.-I. Huang is a member of the national enhanced passive Covid-19 vaccine safety surveillance team in Taiwan. J. Buttery has served as an independent data monitoring committee member for CEPI SPEAC, GSK, Serum Institute of India, SK Biosciences and Clover Vaccines. His employer Murdoch Children’s Research Institute is compensated for his time. A. Greinacher reports grants and non-financial support from Aspen, Boehringer Ingelheim, MSD, Bristol Myers Squibb (BMS), Paringenix, Bayer Healthcare, Gore Inc., Rovi, Sagent, Biomarin/Prosensa, personal fees from Aspen, Boehringer Ingelheim, MSD, Macopharma, BMS, Chromatec, Werfen, nonfinancial support from Boehringer Ingelheim, Portola, Ergomed, GTH e.V. outside the submitted work. No other authors report conflicts of interest. Parts of the German results reported have been obtained in a study conducted by Universitätsmedizin Greifswald under service contract No. EMA/2021/17/TDA. The views expressed are the personal views of the authors and may not be understood or quoted as being made on behalf of or reflecting the position of the European Medicines Agency or one of its Committees or Working Parties. The Taiwan VITT case information was based on data provided by the Vaccine Adverse Event Reporting System, operated by Taiwan Centers for Disease Control., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Parents are the primary decision makers for their children's vaccination, yet, we have limited knowledge on what influences their decision making related to COVID-19 vaccination. The study aimed to understand these different considerations that shape the decisions of parents of children aged 5-11 years old., Methods: We conducted a qualitative study that included online focus group discussions (FGDs) with parents of children aged 5-11 years old. Data was collected between July 26th, 2022, and February 15th, 2023. A total of eight FGDs were conducted, audio-recorded and transcribed verbatim. Thematic analysis was conducted, and peer debriefing was used to ensure methodological rigor., Results: Findings revealed that parents of vaccinated and unvaccinated children employed language of risk-benefit analysis to inform their decision-making. Parents of vaccinated children highlighted concerns about spreading COVID-19, family member's health, and long COVID-19. For parents of unvaccinated children, they perceived potential vaccine side effects as more harmful than the risks associated with COVID-19. Participants contended that there was a lack of transparency from the government and public health agencies, highlighting inconsistent messaging which had fractured their trust in COVID-19-related recommendations and mandates., Conclusions: Our results indicate that improved transparency on how evidence is developed and why recommendations and mandates shift during the pandemic would foster trust in the government and public health agencies. Open communication with health providers on the potential risks and benefits would also improve caregivers confidence in the vaccine., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Shaun Morris reports financial support was provided by Public Health Agency of Canada. Pierre-Philippe Piche-Renaud reports a relationship with Pfizer that includes: funding grants. Shaun K. Morris reports a relationship with Pfizer that includes: board membership. Shaun K. Morris reports a relationship with GlaxoSmithKline Inc. that includes: speaking and lecture fees. Shaun K. Morris reports a relationship with Sanofi Pasteur Inc. that includes: board membership. Shaun K. Morris reports a relationship with Apotex that includes: board membership. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Conflicts of interest PPPR has previously been a co-investigator on an investigator-led project funded by Pfizer that is unrelated to the present study. SKM has received honoraria for lectures from GlaxoSmithKline and has been a member of ad hoc advisory boards for Pfizer, Sanofi Pasteur, and Apotex, all unrelated to this study. All other authors declare that they have no conflicts of interest., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Several studies described that COVID-19 vaccinations can cause menstrual disorders. Our study aimed to describe whether this also resulted in more general practitioner (GP) consultations for menstrual disorders after COVID-19 vaccination, based on a large cohort study., Methods: A retrospective self-controlled cohort study was performed including vaccinated women in 2021 aged 12-49 years from two large, representative GP databases in the Netherlands. Incidence rates and incidence rate ratio's (IRR) were calculated using Poisson regression, adjusting for SARS-CoV-2 infection as time-varying confounder. The exposed period was set at maximum six months after each COVID-19 vaccination and the non-exposed period was defined as all-time outside the exposed period., Results: The cohort included 631,802 women, of which 18,986 (3 %) consulted the GP for a menstrual disorder during 2021. Increased GP consultations were observed among 12-14 year olds for amenorrhea/hypomenorrhea/oligomenorrhea (IRR: 1.85, 95 % CI: 1.30-2.65) and irregular/frequent menstruation (IRR: 1.33, 95 % CI: 1.06-1.69) after COVID-19 vaccination in general, and after Pfizer/BioNTech vaccination (IRR: 1.87, 95 % CI: 1.31-2.67 for amenorrhea/hypomenorrhea/oligomenorrhea and IRR: 1.35, 95 % CI: 1.06-1.70 for irregular/frequent menstruation). Persons from this age group were in general also vaccinated with Pfizer/BioNTech. No increase in the frequency of GP consultations were observed for older age groups, other vaccine brands, and potential risk groups., Conclusion: For the majority of women, no increased GP consultations for menstrual disorders was found. Solely for the youngest age group (12-14 year olds) increased GP consultations for specific types of menstrual disorders was found after Pfizer/BioNTech vaccination., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To measure and evaluate the impact of receiving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines in pregnancy on immunoglobulin G (IgG) and immunoglobulin A (IgA) titres in maternal and infant samples., Design: Prospective cohort study., Setting: Tertiary obstetric centre., Population or Sample: 52 pregnant women who received one or more SARS-CoV-2 vaccine doses during pregnancy and their neonates., Methods: IgG and IgA concentrations against SARS-CoV-2 antigens were measured from samples collected at delivery and 4-6 weeks postpartum and compared using Spearman correlations., Main Outcome Measures: Maternal and infant IgG and IgA titres in response to vaccination and infection in pregnancy., Results: In maternal serum collected at delivery, participants without evidence of prior infection who received 3 + doses of a SARS-CoV-2 vaccine had higher Anti-Spike (S) IgG geometric mean concentrations (log 10 AU/mL)(GMC) than those who received 2 doses (3 + Doses = 5.00, 2 Doses = 4.60, p = 0.08). The differences in IgG Anti-S GMC were statistically significant in cord serum, and in postpartum samples of maternal serum, infant serum and breast milk (Cord GMCs: 3 + Doses = 5.32, 2 Doses = 4.98, p < 0.05; Postpartum maternal serum GMCs: 3 + Doses = 5.25, 2 Doses = 4.57, p < 0.001; Postpartum infant serum GMCs: 3 + Doses = 5.10, 2 Doses = 4.72, p = 0.03; Postpartum breast milk GMCs: 3 + Doses = 2.61, 2 Doses = 1.94, p < 0.0001). Among participants with 3 + Doses, those with evidence of SARS-CoV-2 infection had statistically significant higher anti-S IgG GMCs than those without prior infection (Maternal serum at delivery: SARS-CoV-2+=5.65, SARS-CoV-2-=5.00, p = 0.004; Cord: SARS-CoV-2+=5.68, SARS-CoV-2-=5.32, p = 0.02; Postpartum maternal serum: SARS-CoV-2+=5.66, SARS-CoV-2-=5.25, p < 0.001; postpartum infant serum: SARS-CoV-2+=5.50, SARS-CoV-2-=5.10, p = 0.003; Postpartum breast milk: SARS-COV-2+=3.25, SARS-COV-2-=2.61, p = 0.009). Significant positive correlations were found for anti-S IgG titres between paired maternal and infant samples at delivery and postpartum (Delivery: R = 0.91, p < 0.001; postpartum: R = 0.86, p < 0.001)., Conclusions: Receipt of a SARS-CoV-2 vaccine and SARS-CoV-2 infection elicit strong IgG and IgA antibody responses in pregnant women with evidence of transplacental transfer to the fetus., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: IK, CM, EM, GA, JA, CE, AJ, MK, MM, GT, IS and DM have no conflicts to disclose. MS has been an investigator on projects funded by GlaxoSmithKline, Merck, Moderna, Pfizer, Sanofi-Pasteur, Seqirus, Symvivo and VBI Vaccines, with funds paid to his institute. MS is supported via salary awards from the BC Children’s Hospital Foundation and Michael Smith Health Research BC., (Copyright © 2024. Published by Elsevier Ltd.)

Purpose: Parental human papillomavirus (HPV) vaccine hesitancy contributes to delays or refusals in adolescent uptake. It is unclear if COVID-19 vaccine hesitancy has further impacted the low HPV vaccine uptake trends among underrepresented minorities. This study examines the relationship between COVID-19 vaccine intent and HPV vaccine hesitancy among parents for their adolescents in communities with low vaccine uptake in Los Angeles County., Methods: Parents from a school-based academic enrichment program serving low-income, first-generation immigrant families completed an online cross-sectional survey to understand parental HPV vaccine hesitancy, adolescent HPV vaccine behavior, and attitudes towards other vaccines, including intent to receive COVID-19 vaccines. In March 2021, parents with children ages 9-17 years completed online surveys. Using multivariate logistic regression models, we examined whether low parent intent to vaccinate their adolescent against COVID-19 was associated with hesitancy to vaccinate against HPV., Results: A total of 291 surveys were completed. Among parents with high HPV vaccine hesitancy for their adolescent, 33 % did not intend to vaccinate their adolescent against COVID-19 compared to 7 % among parents with low HPV vaccine hesitancy. Low parent intention to vaccinate adolescent against COVID-19 was associated with higher HPV vaccine hesitancy (p < 0.01) after controlling for parent nativity status, medical mistrust, receiving the flu vaccination and negative HPV information., Discussion: Our findings indicate associations between low parental COVID-19 vaccine intent and higher HPV vaccine hesitancy for their adolescent. Identifying community-relevant health interventions to address parental vaccine hesitancy across multiple child and adolescent vaccines may help to achieve equitable vaccine uptake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Information on the magnitude and duration of antibody levels after COVID-19 vaccination in different groups may be useful for prioritizing of additional vaccinations., Methods: Serum samples were collected every six months in a prospective cohort study among adults in the Netherlands. Geometric mean concentrations (GMCs) of antibodies against the receptor binding domain of the SARS-CoV-2 spike protein were calculated after the primary series, first, and second booster vaccinations. Effects of age (18-59 vs 60-85 years) and medical risk conditions on GMC 2-6 weeks and 21-25 weeks after each vaccination, and on waning during 3-25 weeks after each vaccination, were estimated by linear regression., Results: We included 20,640, 15,229 and 8,392 samples collected after primary, first and second booster vaccination, respectively. GMCs at 2-6 and 21-25 weeks after primary series were lower in participants with older age or medical risk conditions. After the first booster, older age was associated with lower GMC at 2-6 weeks and at 21-25 weeks. Waning after the first and second boosters (only 60-85) was not associated with age or medical risk conditions., Conclusions: Since antibody differences by age and medical risk groups have become small with increasing number of doses, other factors such as COVID-19 disease severity rather than antibody levels are useful for prioritization of additional vaccinations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To develop effective private donation campaigns that support vaccine distribution in low- and middle-income countries (LMICs), one must understand donors' willingness to give, response to stimuli, and preferences for program management. We use a contingent valuation method to estimate United States citizens' willingness to give to nongovernmental COVID-19 immunization programs in LMICs during the emergency phase of the pandemic. Using split-sample treatments, we evaluate the impact of the immunization program administrator (generic NGO or COVAX) and the role of priming communications on inequality in income and vaccination rates between the US and recipient countries. Results show that the median American would donate $42 towards global immunization programs. Preferences for program management and responses to priming communications are heterogeneous across political affiliations, after controlling for altruistic motives, experiences with COVID, giving behaviors, and sociodemographic characteristics. Specifically, Democrats and Independents are more likely to donate to the COVAX-administered fund, and more responsive to priming statements regarding vaccine-gaps. Policy implications are discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Strategies to increase COVID-19 vaccine coverage require an understanding of the extent and drivers of vaccine hesitancy and trust in government related to COVID-19 vaccine programs, especially in low-resource communities., Methods: We conducted a cross-sectional household survey post-COVID-19 vaccine introduction among adults (n = 362) in four municipalities in Sarlahi District, Nepal from August to December 2022. The survey included modules on participant demographics and socioeconomic factors and vaccine hesitancy, information seeking, and trust in authorities related to COVID-19 vaccination., Results: Of the study participants, 38.4 % expressed hesitancy related to COVID-19 vaccination. The adjusted odds of being "vaccine hesitant" were significantly lower among the older adults (51+ years) relative to younger (<30 years) (aOR: 0.49, CI: 0.24-0.97) and among males relative to females (aOR: 0.51, CI: 0.26, 0.95). The study population highly trusted the government's handling of the COVID-19 pandemic. While for most, self-reported access to vaccination opportunities was high (88.4 %), 70.4 % of participants did not know if vaccines were in stock at their local vaccination facility. Commonly reported statements of misinformation include the vaccine being developed in a rush or too fast (21.5 %), COVID-19 infection can be effectively treated with ayurvedic medicine(16.3 %) and obtaining immunity from natural infection is better than through vaccination (19.9 %). The primary sources of information on COVID-19 programs were family and friends (98.6 %), healthcare professionals (67.7 %), Female Community Health Volunteers (FCHVs) (61.9 %), television (56.4 %), and radio (43.1 %)., Conclusion: Although many respondents expressed concerns about COVID-19 effectiveness and safety, a high proportion trusted COVID-19 information provided by healthcare workers and approved of the government's response to the pandemic. This study highlights an opportunity to design new evidence-based communication strategies to improve vaccine confidence delivered through frontline government healthcare workers. Approaches could be targeted to certain communities in the region shown to have higher vaccine hesitancy, including younger people and women., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Though widely applied in other epidemiological fields, the case-cohort study design has seen little application in the field of vaccinology. Case-cohort studies use probabilistic sampling and reweighting to draw inferences about effects (in this case vaccine efficacy) at the population level in an efficient manner. The SARS-CoV-2 pandemic was met with high vaccine uptake, and high rates of population testing prior to the emergence of Omicron variants of concern, in Ontario, Canada, providing an ideal environment for application of case-cohort methodology. We combined a population-based case line list and vaccination database for the province of Ontario between December 2020 and October 2021. Risk of infection after vaccination was evaluated in all laboratory-confirmed vaccinated SARS-CoV-2 cases, and a 2 % sample of vaccinated controls, evaluated using survival analytic methods, including construction of Cox proportional hazards models. Vaccination status was treated as a time-varying covariate. First and second doses of SARS-CoV-2 vaccine markedly reduced risk of infection (first dose efficacy 68 %, 95 % CI 67 %-69 %; second dose efficacy 88 %, 95 % CI 87-88 %). In multivariable models, extended dosing intervals were associated with lowest risk of breakthrough infection (HR for redosing 0.64 (95 % CI 0.61-0.67) at 6-8 weeks). Heterologous vaccine schedules that mixed viral vector vaccine first doses with mRNA second doses were significantly more effective than mRNA only vaccines. Risk of infection largely vanished during the time period 4-6 months after the second vaccine dose, but rose markedly thereafter. We conclude that a case-cohort design provided an efficient means to identify strong protective effects associated with SARS-CoV-2 vaccination in real time, and also served to quantify the timing and magnitude of infection breakthrough risk in the same cohort. Heterologous vaccination and extended dosing intervals improved the durability of immune response., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: David Fisman reports financial support was provided by Canadian Institutes of Health Research. David Fisman reports a relationship with Pfizer Inc that includes: consulting or advisory. David Fisman reports a relationship with Seqirus Inc that includes: consulting or advisory. David Fisman reports a relationship with AstraZeneca Canada Inc that includes: consulting or advisory. David Fisman reports a relationship with Merck & Co Inc that includes: consulting or advisory. David Fisman reports a relationship with Sanofi Pasteur Inc that includes: consulting or advisory. David Fisman reports a relationship with Elementary Teachers’ Federation of Ontario that includes: paid expert testimony. David Fisman reports a relationship with Ontario Nurses’ Association that includes: paid expert testimony. Ashleigh Tuite reports a relationship with Public Health Agency of Canada that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

We aimed to characterise vaccine-induced protection against COVID-19 during five waves caused by Variants of Concern (VOCs). This is a nested case-control study of 3,972 HCW primarily vaccinated with CoronaVac (98%) that evaluated symptomatic SARS-CoV-2 breakthrough infections (BI) in almost two-years follow-up until the 3rd Omicron wave. Predictors of protection against SARS-CoV-2 BI were analysed using conditional logistic regression models. We included 1,491 SARS-CoV-2 breakthrough cases, mostly mild, and 2,962 controls. Most participants (90%) had received at least one booster before the onset of the Omicron waves, mainly BNT162b2. A multivariate logistic regression showed that vaccine-induced protection against BI wanes after six months regardless of the number of monovalent booster doses. Additionally, booster dose with BNT162b2 showed a trend for higher protection compared to CoronaVac during the Omicron waves. In conclusion, immunity of monovalent booster doses against SARS-CoV-2 is short-lasting. Individuals previously vaccinated with an inactivated vaccine should receive a BNT162B2 booster dose., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [AMCS received a grant from Instituto Butantan (2021-2022) as Principal Investigator of a study that evaluated the immunogenicity and safety of CoronaVac in immunocompromised patients]., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: University students have a unique perspective on vaccination because of their recent or perhaps newly acquired autonomy and ability to make health-related decisions. The development of the COVID-19 vaccine in 2020 and its implementation over the past few years was accompanied by much information and communication about vaccination requirements and safety, which may have affected students' perspectives on vaccination and vaccine requirements more broadly. This analysis describes current vaccine policies at several universities and evaluates student respondents' perceptions of and agreement with university vaccine requirements., Methods: A 32-question survey was administered to undergraduate, graduate, and professional students attending four Pennsylvania universities in March-May 2023; 2,223 students responded to the survey. The survey included questions about vaccine requirements, agreement with vaccine requirements, and knowledge of selected vaccines. These responses were compared with the actual vaccine requirements and recommendations of the four universities., Results: Most respondents agreed with university vaccine requirements, though knowledge of those requirements varied, with many unaware of which were required. University requirement of the COVID-19 vaccine was not associated with being vaccinated for COVID-19. However, while the requirement itself was not related to vaccine uptake, respondents' perception of a requirement was. Respondents were more likely to report COVID-19 vaccination and influenza vaccination if they believed their university required those vaccines. Respondents were more likely to approve of a vaccine requirement if their perception was that their university required that vaccine., Conclusions: Overall, student respondents were supportive of their institution's vaccine requirements, but many lacked information about those requirements. Clear messaging using multiple modes of communication about vaccines and vaccine requirements may improve students' knowledge of vaccines and result in a corresponding increase in vaccine uptake., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Charlotte Moser reports financial support was provided by The Emily Koenig Meningitis Fund of the Philadelphia Foundation. Charlotte Moser reports financial support was provided by Childrens Hospital of Philadelphia. Barbara Kuter reports a relationship with Moderna Inc that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Kidney transplant recipients (KTRs) show poor antibody response to the SARS-CoV-2 vaccine. There is limited data on immune response to non-mRNA vaccines in KTRs. We studied the antibody response to the SARS-CoV-2 non-mRNA vaccine in a cohort of kidney transplant recipients., Methods: We included KTRs following up in the tertiary care transplant outpatient clinic from February to April 2022. SARS-CoV-2 spike protein IgG antibody titers were measured using chemiluminescence immunoassay. Data on demographic, clinical, and laboratory characteristics were collected, and patients were characterized by the history of Coronavirus disease 2019 (COVID-19) infection in the past and the number of vaccine doses received. Predictors of antibody response were obtained using multivariate regression analysis., Results: S1/S2 IgG anti-SARS-CoV-2 antibodies were detected in 197 (87.94%) of 224 KTRs with a median [IQR] titers of 307.5 AU/ml [91 AU/ml - 400 AU/ml]. Neutralizing range antibody titers were found in 170/224 (75.9%) KTRs. Diabetes at the time of vaccination was associated with poorer antibody response (aOR 0.31, 95% confidence interval [CI] - 0.10, 0.90; p = 0.032) and vaccination with Covishield™ (ChAdOx1 nCoV- 19 Recombinant CoronaVirus Vaccine) showed higher antibody response as compared to Covaxin™ (BBV152) (aOR 5.04, 95% CI - 1.56, 16.22; p = 0.007). Graft dysfunction at baseline was associated with poorer antibody response., Conclusions: KTRs showed good antibody response after SARS-CoV-2 vaccination with non-mRNA vaccines. Diabetes and graft dysfunction were associated with poor seroconversion rates., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: In late 2022, China became the first country to roll out mucosal COVID-19 vaccines. No prior study has yet compared the immunization stress-related responses (ISRR) among different routes of COVID-19 vaccine delivery. We aimed to compare the immunization-related psychological stress and ISRR between mucosal and intramuscular COVID-19 vaccines., Methods: A cross-sectional questionnaire survey using a biopsychosocial framework design was performed from January 11 to 20, 2023. Adults with COVID-19 vaccination were eligible for the study, and a total of 1073 adults participated with community-based sample. Primary outcomes were the psychological stress levels and prevalence of ISRR. Multivariate regression models were employed to compare these outcomes between the two vaccination groups. The potential mediating effects of stress on vaccination and ISRR were examined using bootstrap sampling method. To further ensure the robustness of our results, sensitivity analysis with propensity score matching was performed., Findings: In the univariate analysis, participants who received mucosal vaccination reported significantly lower stress levels compared to those who received intramuscular vaccination (3.39 ± 3.02 vs. 3.93 ± 3.24, P = .006). The prevalence of overall ISRR was significantly lower in the mucosal group compared to the intramuscular group (38.4% vs. 47.9%, P = .002). Multivariate regression models revealed that participants who received mucosal vaccination had a significantly lower stress level (β = -0.516, 95% CI: -0.852 to -0.180; P = .003) and 38.7% fewer overall ISRR (OR = 0.613, 95% CI: 0.427 to 0.881; P = .008), particularly in terms of neurological symptoms. The immunization-related stress mediated the association between vaccination type and ISRR, with indirect effects estimated at 0.0663 (95% CI: 0.0195 to 0.1346) for overall ISRR., Conclusions: Mucosal COVID-19 vaccination was associated with reduced psychological stress and physical responses, as compared to intramuscular vaccination, which may contribute to increased trust and compliance with routine or mass vaccination efforts in the future., Competing Interests: Declaration of competing interest Authors declare no conflict of interests., (Copyright © 2024. Published by Elsevier Ltd.)

Amid the global response to the COVID-19 pandemic, Cambodia emerges as a notable exemplar, boasting a remarkable vaccination rate of 91% of its population by the end of 2021. This success can be attributed to a multifaceted approach encompassing strong governmental leadership, robust vaccine management, and effective risk communication. Despite notable success, challenges persisted in reaching unvaccinated segments of the population. Rapid Coverage and Community assessments (RCCAs) supported by UNICEF were deployed in 2022 and 2023 to support Government efforts in expanding vaccination reach to missed populations and bolster COVID-19 booster doses. RCCAs were conducted across 8 provinces, assessing 13,547 individuals from 87 low-coverage communes to identify not vaccinated people and understand their barriers. Overall, only seven percent missed any dose of C-19 vaccine, Disabilities and lack of education correlated with higher rates of zero doses (20.8% and 17.8%, respectively), with concerns about personal health conditions (25%) and adverse effects (10%) cited as top reasons for non-vaccination. RCCAs, differing from routine monitoring, utilized purposive sampling to identify barriers to vaccine access and uptake. Findings informed adaptive strategies by government and partners to enhance outreach in low-coverage areas. The RCCAs played a crucial role at the local level in ensuring vaccinations reached overlooked populations, providing innovative solutions and supporting UNICEF's national strategies. By the end of 2022, Cambodia achieved a high subnational coverage, contributing to a national coverage of 95% for primary doses and nearly 70% for the first booster for everyone above three years old. RCCAs also fostered local coordination, facilitating resource sharing, and coordinated action for more effective local outreach and community trust. Integration of RCCAs into national immunization programs is recommended to develop targeted outreach for underserved populations, including zero-dose children and communities. Cambodia's adaptation of RCCAs during the pandemic offers valuable insights into identifying and engaging missed populations, highlighting the importance of community involvement and targeted interventions for future pandemic preparedness, and achieving more equitable health outcomes in the longer-term., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Some public health professionals have expressed concern that the COVID-19 pandemic has increased vaccine hesitancy about routine childhood vaccines; however, the differential prevalence of vaccine hesitancy about specific vaccines has not been measured., Methods: Data from the National Immunization Survey-Child COVID-19 Module (NIS-CCM) were analyzed to assess the proportion of children ages 6 months-17 years who have a parent with hesitancy about: COVID-19, influenza, human papillomavirus (HPV) (for children ≥ 9 years) vaccines, and "all other childhood shots." Interviews from October 2022 through April 2023 were analyzed., Results: The percentage of children with a vaccine-hesitant parent varied by vaccine. 55.9% of children had a parent hesitant about COVID-19 vaccine, 30.9% hesitant about influenza vaccine, 30.1% hesitant about HPV vaccine, and 12.2% had a parent hesitant about other vaccines such as measles, polio, and tetanus., Conclusion: The study findings suggest that differential interventions and communications to parents be used to educate about COVID-19, influenza, HPV, and routine childhood vaccinations because the hesitancy levels differ widely., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Among new vaccine technologies contributed to the control of the COVID-19 pandemic, ChAdOx1 nCoV-19, a chimpanzee adenovirus (ChAd)-vector vaccine expressing the SARS-CoV-2 spike protein, could be administered globally owing to its low production cost and lack of a requirement for frozen storage. Despite its benefits, most recipients have reported immediate inflammatory reactions after the initial dose vaccination. We comprehensively examined the immune landscape following ChAdOx1 nCoV-19 vaccination based on the single-cell transcriptomes of immune cells and epigenomic profiles of monocytes. Monocyte and innate-like activated T cell populations expressing interferon-stimulated genes (ISGs) increased 1 day post-vaccination with appearance of distinct subtype of ISG-activated cells, returning to baseline by day 14. Pre-treatment with oral corticosteroids effectively curtailed these ISG-associated inflammatory responses by decreasing chromatin accessibility of major ISGs, without hampering vaccine immunogenicity. Our findings provide insights into the human immune response following ChAd-based vaccination and propose a method to reduce inflammatory side effects., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: [Jeong Seok Lee reports financial support was provided by Korea Advanced Institute of Science and Technology. Jeong Seok Lee reports a relationship with Korea Advanced Institute of Science and Technology that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.]., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objectives: To determine demographic and clinical characteristics associated with uptake of COVID-19 vaccines among pregnant women, and quantify the relationship between vaccine uptake and admission to hospital for COVID-19., Background: Pregnant women are at increased risk of severe adverse outcomes from COVID-19. Since April 2021, COVID-19 vaccines were recommended for pregnant women in the UK. Despite this, evidence shows vaccine uptake is low. However, this evidence has been based only on women admitted to hospital, or on qualitative or survey-based studies., Methods: Retrospective cohort study including all pregnancies ending between 18 June 2021 and 22 August 2022, among adult women registered with a Northwest London general practice. Statistical analyses were mixed-effects multiple logistic regression models. We conducted a nested case-control analysis to quantify the relationship between vaccine uptake by end of pregnancy and hospitalisation for COVID-19 during pregnancy., Results: Our study included 47,046 pregnancies among 39,213 women. In 26,724 (57%) pregnancies, women had at least one dose of vaccine by the end of pregnancy. Uptake was lowest in pregnant women aged 18-24 (33%; reference group), Black women compared with White (37%; OR 0.55, 95% CI: 0.51 to 0.60), and women in more deprived areas (50%; reference group). Women with chronic conditions were more likely to receive the vaccine than women without (Asthma OR 1.21, 95% CI: 1.13 to 1.29). Patterns were similar for the second dose. Women admitted to hospital were much less likely to be vaccinated (22%) than those not admitted (57%, OR 0.22, 95% CI: 0.15 to 0.31)., Conclusions: Women who received the COVID-19 vaccine were less likely to be hospitalised for COVID-19 during pregnancy. COVID-19 vaccine uptake among pregnant women is suboptimal, particularly in younger women, Black women, and women in more deprived areas. Interventions should focus on increasing uptake in these groups to improve health outcomes and reduce health inequalities., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Paul Aylin reports financial support was provided by NIHR Patient Safety Translational Research Centre. Sonia Saxena reports financial support was provided by NIHR School for Public Health Research. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The global COVID-19 vaccination campaign, with 13.53 billion doses administered by early 2024, has significantly reduced severe illness and mortality. However, potential adverse effects, such as Postural Orthostatic Tachycardia Syndrome (POTS), have raised concerns. This systematic review evaluates the incidence, mechanisms, and clinical implications of POTS following COVID-19 vaccination., Methods: A systematic search of PubMed, EMBASE, and Web of Science was conducted up to June 7, 2024, following PRISMA guidelines to identify studies related to COVID-19 vaccines and POTS. Eligible studies included randomized controlled trials, cohort studies, cross-sectional studies, case-control studies, case series, and case reports. Screening, data extraction, and quality assessment were independently performed by two reviewers using the Joanna Briggs Institute Checklists and the Newcastle-Ottawa Scale., Results: Of the 1,531 articles identified, 10 met the inclusion criteria, encompassing a total of 284,678 participants. These studies included five case reports, two case series, one cross-sectional study, one prospective observational study, and one cohort study. The cohort study reported that the odds of new POTS diagnoses post-vaccination were 1.33 (95% CI: 1.25-1.41) compared to the 90 days prior. In contrast, the post-infection odds were 2.11 (95% CI: 1.70-2.63), and the risk of POTS was 5.35 times higher (95% CI: 5.05-5.68) post-infection compared to post-vaccination. Diagnostic findings across studies included elevated norepinephrine levels and reduced heart rate variability. Reported management strategies involved ivabradine, intravenous therapies, and lifestyle modifications., Conclusion: The risk of POTS following COVID-19 vaccination is lower than that observed post-SARS-CoV-2 infection; however, existing studies are limited by small sample sizes and methodological variability. Further research is needed to clarify the incidence, mechanisms, and long-term outcomes of vaccine-related POTS to inform effective clinical management strategies., Competing Interests: Declarations Ethical approval Not required. Conflict of interest The authors report no conflict of interest., (© 2024. The Author(s).)

Background: The vaccine supply chain (VSC) integrates all activities from production to dispensing, characterized by complexity and low responsiveness. This study aims to define key performance indicators (KPIs) to evaluate the logistic and operational performance during the COVID-19 National Vaccination Plan in Colombia., Methods: This study employed the design science research (DSR) methodology to develop a dashboard for monitoring COVID-19 vaccination progress. DSR is a problem-solving paradigm focused on conceiving, testing, and evaluating artifacts to tackle specific challenges. The dashboard integrated a set of Key Performance Indicators (KPIs) that incorporated three dimensions: epidemiological, humanitarian, and logistical. Both, the dashboard and the KPIs underwent validation through three iterative DSR cycles, in collaboration with both private and public health stakeholders., Results: A set of 38 validated KPIs, grouped into eight categories, was consolidated into an online dashboard. This tool enabled real-time tracking of the National Vaccination Plan at both national and departmental levels, providing stakeholders with a comprehensive view of the vaccine supply chain. It also allowed for the assessment and comparison of the execution and effectiveness of public policies., Conclusions: These KPIs supported decision-making from a logistical standpoint, enhancing the planning, preparation, and continuous improvement of mass vaccination processes, thereby increasing their potential impact even further., Competing Interests: Declarations Ethics approval and consent to participate Not applicable. Consent for publication All authors have read and agreed to the published version of the manuscript. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Introduction: Migrant populations (asylum seekers, permit holders, refugees, and undocumented migrants) living in South Africa face various individual, social, and physical circumstances that underpin their decisions, motivation, and ability to receive the COVID-19 vaccine. We conducted a qualitative study to explore the experiences and perceptions of migrant populations in South Africa on COVID-19 vaccines to inform recommendations for improved COVID-19 immunization., Methods: We conducted an Interpretative Phenomenological Analysis (IPA) with 20 asylum seekers, permit holders, refugees, and undocumented migrants living in South Africa. We applied a maximum variation purposive sampling approach to capture all three categories of migrants in South Africa. Semi-structured interviews were conducted and recorded electronically with consent and permission from the study participants. The recordings were transcribed and analyzed thematically following the IPA using Atlas.ti version 9., Results: Four major reflective themes emanated from the data analysis. (1) While some migrants perceived being excluded from the South African national immunization program at the level of advertisement and felt discriminated against at the immunization centers, others felt included in the program at all levels. (2) Skepticism, myths, and conspiracy theories around the origin of SARS-CoV-2 and the COVID-19 vaccine are pervasive among migrant populations in South Africa. (3) There is a continuum of COVID-19 vaccine acceptance/hesitancy ranging from being vaccinated through waiting for the chance to be vaccinated to refusal. (4) Accepting the vaccine or being hesitant follows the beliefs of the participant, knowledge of the vaccine's benefits, and lessons learned from others already vaccinated., Conclusion: COVID-19 vaccine inclusiveness, awareness, and uptake should be enhanced through migrant-aware policies and actions such as community mobilization, healthcare professional training, and mass media campaigns., Competing Interests: Declarations Ethics approval and consent to participate Ethics approval was obtained from the Humanities and Social Sciences Research Ethics Committee of the University of the Western Cape (HS20/6/6). The following ethical conditions were adhered to after obtaining ethics clearance: Informed consent was signed by each participant before participating in the in-depth interviews. Before they signed the informed consent form, each participant was debriefed on the research purpose, aims, and objectives of the study and the research process. The participants were also informed of their rights to withdraw from the study and the interview at any time they wanted without any consequences, like being reported to the authorities of their immigration status. Participants were encouraged to ask questions to obtain clarity about the study. Permission was obtained from the different social organizations where the participants were sampled. Participants also agreed that the interview sessions should be audio recorded. To ensure confidentiality, we only used the first names of the participants and their countries of origin when reporting excerpts from their interviews. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

The emergence of the omicron variant and its sub-lineages has necessitated vaccine updates for coronavirus disease 2019. In September 2023, the U.S. Food and Drug Administration approved an updated BNT162b2 vaccine targeting the omicron XBB.1.5 variant, which was initiated in Korea in October 2024. This study demonstrates the adverse events reported through active nationwide surveillance after XBB.1.5 vaccination in Korea. Since October 19, 2023, the Korea Disease Control and Prevention Agency has conducted daily Short Message Service surveys to collect data on health issues, fever, vaccination site reactions, systemic symptoms, impact on daily life, and healthcare visits. Among 20,180 respondents, 27.9% reported health issues. Adverse reactions peaked on day 1 (28.7%), including pain at the vaccination site, muscle pain, fatigue, and fever. These findings elucidate the short-term safety of the XBB.1.5 vaccine and support its co-administration with the influenza vaccine, reducing vaccine hesitancy and achieving herd immunity., Competing Interests: The authors have no potential conflicts of interest to disclose., (© 2024 The Korean Academy of Medical Sciences.)

Background: Immune thrombocytopenic purpura (ITP) is a disease characterized by a decrease in platelet count, which can be triggered by various factors, including viral infections and vaccination. With the widespread vaccination against COVID-19, concerns have arisen regarding a possible link between the vaccine and the exacerbation of ITP. This study aims to comprehensively evaluate the impact of COVID-19 vaccination on ITP patients, including associated risks and outcomes., Methods: A comprehensive search will be conducted in multiple electronic databases (including PubMed, Web of Science, EMBASE, Cochrane Library, CNKI, Wan Fang, VIP, and CBM) to identify relevant studies. This study will include randomized controlled trials, cohort studies, case-control studies, and case series evaluating the impact of COVID-19 vaccination on ITP patients. The primary outcome measure is the change in platelet count, while secondary outcome measures include the occurrence of thromboembolic events, bleeding complications, ITP recurrence rate, impact of ITP exacerbation, and adverse events. Data will be summarized and analyzed using Review Manager Software (RevMan) V.5.4. In addition, subgroup analyses will be performed to explore potential sources of heterogeneity., Results: It is anticipated that different types of COVID-19 vaccines may have varying impacts on ITP patients, leading to potential differences in outcomes. This study aims to comprehensively evaluate the potential impact of COVID-19 vaccination on ITP patients and provide reference for clinical decision-making., Conclusions: The results of this systematic review and meta-analysis will provide crucial information on COVID-19 vaccination for ITP patients and clinicians, contributing to guiding vaccination decisions and monitoring potential impacts after vaccination., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: While evidence of efficacy, safety, and technical feasibility is crucial when introducing a vaccine, it is equally important to consider the psychological, social, and political factors influencing vaccine acceptance. This study aims to identify the factors contributing to COVID-19 vaccine hesitancy among adults in Tehran, Iran., Methods: The study employed a descriptive and analytical cross-sectional design carried out from 2021 to 2022. It involved 260 eligible individuals residing in the catchment areas of Tehran and Shahid Beheshti Universities of Medical Sciences who declined to receive the COVID-19 vaccine, selected through systematic sampling. Data collection was accomplished through a researcher-developed questionnaire and analyzed using SPSS 26 software. The analysis utilized descriptive statistics and non-parametric tests including Mann-Whitney U, Kruskal-Wallis, and Multiple Linear Regression, to examine the relationships between variables., Results: The average scores (SD) across dimensions were as follows: the individual's health status and perceived risk, 15.53 (1.70); contextual and social effects, 17.68 (2.53); awareness, 14.81 (2.34); and beliefs and concerns. 14.91 (2.64), indicating a concerning situation regarding contextual and social impacts and a moderate status as to other areas. The primary reasons for vaccine refusal included fear, lack of belief in the vaccine, concerns about its reliability, illness, and lack of access or time. Acceptance of the vaccine was associated with education, occupation, marital status, number of children at home, and income reduction due to COVID-19., Conclusion: The findings indicate that fear, lack of belief in the vaccine, concerns regarding its reliability, illness, and lack of access or time were the most important factors influencing reluctance to receive the vaccine. Health organizations should consider these factors when encouraging the population to receive the COVID-19 vaccine., Competing Interests: Declarations Ethics approval and consent to participate Prior to conducting telephone interviews, necessary information regarding the study and its objectives were given to the participants and informed consent was obtained verbally, with audio recordings made for verification. The current study is approved by the Ethics Committee of the Tehran University of Medical Sciences Research Center for Justice in Health (IR.TUMS.NIHR.REC.1400.013). All the used methods were performed in accordance with the relevant guidelines and regulations. It should also be noted that written consent was not necessary for this study because the names of the interviewees were not mentioned in the findings. Moreover, the participants were assured that their information would remain confidential and the data of the study would be analyzed anonymously. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Mosaic nanoparticle vaccines with heterotypic antigens exhibit broad-spectrum antiviral capabilities, but the impact of antigen proportions and distribution patterns on vaccine-induced immunity remains largely unexplored. Here, we present a DNA nanotechnology-based strategy for spatially assembling heterotypic antigens to guide the rational design of mosaic nanoparticle vaccines. By utilizing two aptamers with orthogonal selectivity for the original SARS-CoV-2 spike trimer and Omicron receptor-binding domain (RBD), along with a DNA soccer-ball framework, we precisely manipulate the spacing, stoichiometry, and overall distribution of heterotypic antigens to create mosaic nanoparticles with average, bipolar, and unipolar antigen distributions. Systematic in vitro and in vivo immunological investigations demonstrate that 30 heterotypic antigens in equivalent proportions, with an average distribution, lead to higher production of broad-spectrum neutralizing antibodies compared to the bipolar and unipolar distributions. Furthermore, the precise assembly utilizing our developed methodology reveals that a mere increment of five Omicron RBD antigens on a nanoparticle (from 15 to 20) not only diminishes neutralization against the Omicron variant but also triggers excessive inflammation. This work provides a unique perspective on the rational design of mosaic vaccines by highlighting the significance of the spatial placement and proportion of heterotypic antigens in their structure-activity mechanisms., (© 2024 Wiley-VCH GmbH.)

Introduction: The rapid spread of coronavirus infection COVID-19 among the population of many countries around the world has contributed to the emergence of many genetic variants of SARS-CoV-2. Compared to previous coronavirus variants, the new Omicron variants have shown a noticeable degree of mutation. Virus inactivation is one of the most important steps in the development of inactivated vaccines. The chemical inactivation agents currently used are β-propiolactone and formaldehyde, but there is no uniform standard for designing and specifying the inactivation process., Objective: Evaluation and comparison of the effectiveness of chemical inactivation of two agents, formaldehyde and β-propiolactone against immunogenicity of the Omicron variant of the SARS-CoV-2 virus., Materials and Methods: Nasopharyngeal swabs were used to obtain the SARS-CoV-2 Omicron variant virus. Vero cell culture was used to isolate, reproduce, titrate the virus, and perform a neutralization reaction. The kinetics of studying the inactivation of the virus by chemical agents such as formaldehyde and β-propiolactone was carried out., Results: Studies have been conducted to comparatively evaluate the effectiveness of chemical agents used to inactivate the SARS-CoV-2 virus of the Omicron variant, planned for use in the production of an inactivated whole-virion vaccine. Formaldehyde and β-propiolactone were used as inactivation agents in concentrations of 0.05, 0.1, 0.5% of the total volume of the virus suspension. It has been established that complete inactivation of the virus by formaldehyde in the concentrations used at a temperature of 37 °C occurs within up to 2 hours, and when using beta-propiolactone, within up to 12 hours., Conclusion: Inactivated virus samples have different antigenic activity depending on the concentration of the inactivation agents used. The most pronounced antigenic activity is manifested in samples of the pathogen that were treated with an inactivation agent at a mild concentration of 0.05%. Increasing the concentration of inactivation agent by 5 or more times leads to a significant decrease in the antigenicity of the SARS-CoV-2 virus. With the inactivation modes used, the loss of biological activity of the virus occurs faster and antigenicity is retained largely when treated with formaldehyde.

Humans get SARS-CoV-2 infection mainly through inhalation; thus, vaccine that induces protective immunity at the virus entry site is important for early control of the infection. In this study, two anionic liposome (L)-adjuvanted VLP vaccines against SARS-CoV-2 were formulated. Baculovirus-Sf21 insect cell system was used for production of VLPs made of full-length S, M and E proteins. S protein of one vaccine (L-SME-VLPs) contained furin cleavage site at the S1/S2 junction, while that of another vaccine (L-S'ME-VLPs) did not. Both vaccines were innocuous and immunogenic when administered IP and IN to mice. Mice immunized IP with L-SME-VLPs/L-S'ME-VLPs (three doses, two-weeks intervals) had serum virus neutralizing (VN) antibodies (in falling order of isotype frequency): IgG3, IgA and IgG2a/IgG3, IgA and IgM, respectively. The L-S'ME VLPs vaccine induced significantly higher serum VN antibody titers than the L-SME-VLPs vaccine. All mice immunized IN with both vaccines had significant rise of VN antibodies in their bronchoalveolar lavage fluids (BALF). The VN antibodies in 67% of immunized mice were Th1- isotypes (IgG2a and/or IgG2b); the immunized mice had also other antibody isotypes in BALF. The intranasal L-S'ME-VLPs should be tested further step-by-step towards the clinical use as effective and safe vaccine against SARS-CoV-2., (© 2024. The Author(s).)

Background: In the pursuit of global health security, continuous monitoring of vaccine effectiveness across various viral strains emerges as a crucial imperative. The emergence of SARS-CoV-2 major variants of concern (VOCs), including Alpha, Beta, Delta, and Omicron, has added complexity to the COVID-19 vaccination landscape., Objectives: To assess illness severity, evaluate vaccine efficacy across varying doses and types, and determine effectiveness against major VOCs within the population., Methods: This retrospective cohort study, conducted in Abu Dhabi, United Arab Emirates, focuses on a cohort of 44,073 SARS-CoV-2 positive cases from February 2021 to May 2022, dominated by the Delta and Omicron variants. The study employed a nested case-control design, analyzing hospital admissions for confirmed SARS-CoV-2 infection., Results: Vaccine effectiveness was higher among heterologus-boosted individuals at 87% (95% CI:79%-93%) compared to homologus-boosted individuals at 59% (95% CI: 48%-68%) and fully vaccinated, non-boosted adults at 53% (95% CI: 46%-59%). These findings highlight the importance of heterologous boosting, particularly against rapidly evolving viral variants, offering valuable insights for refining pandemic response strategies., Conclusion: The study underscores the critical need for ongoing assessment and adaptation of vaccination strategies to the evolving viral landscape., (© 2024. The Author(s).)

Introduction: The COVID-19 pandemic focused attention on the importance of vaccine security to national security. Demand for vaccines far exceeded supply when the first COVID-19 vaccines were released. Growing data suggest a non-perfect correlation among vaccine development, production, purchases, deliveries and vaccination rates. As such, the best approach to strengthening vaccine security remains unclear. In this study, we use an operations research/operations management framework to characterise the relationship between vaccine security and key supply chain predictor variables in high-income countries (HICs) and low-income and middle-income countries (LMICs)., Methods: We performed a comparative analysis of vaccine security against eight supply chain variables in a purposive sample of five HICs and five LMICs during the early phase of the pandemic (31 March 2021 and 30 April 2021). All data were obtained from publicly available databases. We used descriptive statistics to characterise our data, basic statistics to compare data and scatter plots to visualise relationships., Results: Our data show greater vaccine security in HICs compared with LMICs (32.2% difference in April 2021; 95% CI 4.2% to 60.3%, p=0.03). We report a significant difference between HICs and LMICs in only two of the eight predictor variables studied. Interestingly, we observed large variation in vaccine security within HICs, with Canada, Israel and Japan being frequent outliers, and within LMICs, with India standing out., Conclusion: Our data suggest a stronger relationship between vaccine security and 'downstream' supply chain variables compared with 'upstream' variables. However, multiple outliers and the lack of an even stronger relationship suggests that there is no magic bullet for vaccine security. To boost vaccine resilience, countries must be well governed and strategically reinforce deficient aspects of their supply chains. Modest strength in multiple domains may be the best approach to counteracting the effect of an unfamiliar, novel pathogen., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: This study aims to identify the factors influencing vaccine hesitancy, willingness and its variation over time in order to inform more responsive strategies for increasing vaccination uptake. The specific objectives are: (1) to describe and compare levels of COVID-19 vaccine hesitancy among the general population in rural and urban settings in West Africa over time and (2) to identify factors associated with COVID-19 vaccination willingness and hesitancy among the general population across five West African countries over time., Design: Following a baseline survey (Wave I), three serial cross-sectional surveys (Waves II-IV) were implemented., Setting: The study was conducted in Burkina Faso, Guinea, Mali, Senegal and Sierra Leone from November 2021 to July 2022., Participants: A total of 13 571 study participants were included in the study (n=4373, n=4593 and n=4605 for survey Waves II, III and IV, respectively). Inclusion criteria were being 18 years or older, living in the study area and willing to provide informed consent. A two-stage sampling strategy was used to select the sample from among the general population., Primary and Secondary Outcomes: Primary outcomes were the variability of vaccine hesitancy over time and across the five West African countries. Secondary outcomes were factors associated with vaccine willingness., Results: A small but steady increase in hesitancy to COVID-19-vaccination can be observed across countries, with an upward trend of vaccine hesitancy reported by 952 participants (33.9 %) in Wave II, 1055 (37.3%) in Wave III and 1089 (38.1%) in Wave IV. Among the countries included, Senegal shows the highest level of vaccine hesitancy ('Definitely no' and 'Probably no' ranging from 50.2% to 56.0% and 26.2 to 28.3%, respectively). At the same time, Senegal has the lowest vaccination coverage overall. Across all five countries and survey waves, the primary factor associated with vaccination willingness is fear of experiencing severe COVID-19 disease (Wave II: OR 0.42, 95% CI 0.34 to 0.51, Wave III: OR 0.48, 95% CI 0.40 to 0.59 and Wave IV: OR 0.54, 95% CI 0.44 to 0.66). Perceived improved financial status seems to influence willingness to get vaccinated negatively (OR 0.57, 95% CI 0.40 to 0.81) and unlike in Western, Educated, Industrialised, Rich and Democratic countries, men seem more reluctant to get vaccinated than women (OR 0.77, 95%, CI 0.65 to 0.93)., Conclusions: Our findings suggest that vaccine hesitancy should be monitored over time to inform communication strategies, which are responsive to changes in vaccination-related public sentiments. Additionally, a focus on social solidarity and the importance of women in vaccination advocacy can help improve COVID-19 vaccination coverage in West Africa., Trial Registration Number: The general protocol is registered on clinicaltrial.gov (protocol number: NCT04912284)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Evidence fails to capture disparities amongst African countries in terms of the measure of administered COVID-19 vaccine doses per 100 people. Assessment of data on doses secured, administered, and supplied was undertaken to investigate quantitative measures that impacted COVID-19 vaccine deployment, thereby emphasizing distribution and supply indicators. We employ a full linear regression to identify independent variables that have an impact on vaccination rates, including macroeconomic indicators such as World Bank Income Classification, Gross Domestic Product (GDP) per capita and various indices such as Health Access and Quality Index, Human Development Index, Global Peace Index, Education Index, Political Stability Index and Government Effectiveness. This analysis aims to construct a statistical model utilizing regression analysis to identify key drivers of COVID-19 vaccine deployment in Africa and offer insights into vaccination disparities in the continent. Recognizing the global importance of achieving high vaccination rates, the study sheds light on specific challenges faced by individual countries within Africa, thereby emphasizing the need for tailored efforts. Beyond COVID-19, the research contributes to understanding the relationship between vaccination rates and social indicators that, potentially impact broader public health concerns and global vaccination programs. This study provides a foundation for informed policymaking to enhance vaccine accessibility, inform targeted programs, and improve individual health systems, thereby addressing broader implications for global health., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Ezezika et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: The aim of this study was to assess the seroconversion rate and percent inhibition of neutralizing antibodies against the wild-type and Omicron variants of SARS-CoV-2 in patients with solid cancer who received two COVID-19 vaccine doses by comparing chemotherapy and nonchemotherapy groups., Methods: This prospective cohort study enrolled 115 cancer patients from Maharaj Nakorn Chiang Mai Hospital, Sriphat Medical Center, Faculty of Medicine, Chiang Mai University, and Chiang Mai Klaimor Hospital, Chiang Mai, Thailand, between August 2021 and February 2022, with data from 91 patients who received two COVID-19 vaccine doses analyzed. Participants received vaccines as part of their personal vaccination programs, including various mRNA and non-mRNA vaccine combinations. Blood samples were collected at baseline, on day 28, and at 6 months post-second dose to assess neutralizing antibodies. The primary outcome was the seroconversion rate against the wild-type and Omicron variants on day 28. Secondary outcomes included seroconversion at 6 months, factors associated with seroconversion, and safety., Results: Among the participants, 45% were receiving chemotherapy. On day 28, seroconversion rates were 77% and 62% for the wild-type and Omicron variants, respectively. Chemotherapy did not significantly affect seroconversion rates (p = 0.789 for wild type, p = 0.597 for Omicron). The vaccine type administered was positively correlated with seroconversion, with an adjusted odds ratio (95% confidence interval) of 25.86 (1.39-478.06) for the wild type and 17.38 (3.65-82.66) for the Omicron variant with the primary heterologous vaccine regimen. Grades 1 and 2 adverse events were observed in 34.0% and 19.7% of participants, respectively., Conclusions: Despite the lower seroconversion rate against the Omicron variant, no significant difference was observed between the chemotherapy and nonchemotherapy groups. COVID-19 vaccinations demonstrated good tolerability in this cohort. These findings highlight the importance of vaccine safety and immunogenicity in cancer patients and can inform tailored vaccination strategies for this vulnerable population., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Chewaskulyong et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)