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Background: Echinococcosis is a zoonotic infectious disease that poses a significant threat to the health of individuals living in rural regions. While vaccination represents a potential strategy for disease prevention, there is currently no effective vaccine available for humans to prevent cystic echinococcosis (CE). This study aimed to design a novel multi-epitope vaccine (MEV) against Echinococcus granulosus for human use, employing immunoinformatics methods. Methods: We identified core epitopes from two key antigens, EgA31 and EgG1Y162, and integrated them into the immunoglobulin variable region of CTLA-4 (CTLA-4lgV) to create the CVE31-162 vaccine construct. The secondary and tertiary structures of the CVE31-162 were established using bioinformatics methods. The interaction between the CVE31-162 and B7 molecules was assessed through molecular dynamics simulations. Finally, both in vitro and in vivo experiments were conducted to validate the effectiveness of the CVE31-162 against the immunological effects of Echinococcus granulosus. Results: Bioinformatics analysis indicated that CVE31-162 exhibits favorable antigenicity, stability, and non-allergenicity. Furthermore, CVE31-162 demonstrated a stable three-dimensional structural model. Molecular docking (MD) and molecular dynamics simulations (MDS) revealed a strong binding affinity between CVE31-162 and B7 molecules. Immune simulation results suggested that the vaccine elicits robust humoral and cell-mediated immune responses. Both in vitro and in vivo experiments demonstrated that immunized mice exhibited significantly elevated levels of antigen-specific antibodies and enhanced lymphocyte proliferation compared to the control group. Conclusions: CVE31-162, which is based on the interaction between CTLA-4 and B7, represents a promising multi-epitope vaccine for Echinococcus granulosus. [ABSTRACT FROM AUTHOR]

Background/Objectives: Haematopoietic stem cell transplantation (HCT) induces profound immunosuppression, significantly increasing susceptibility to severe infections. This review examines vaccinations' necessity, timing, and efficacy post-HCT to reduce infection-related morbidity and mortality. It aims to provide a structured protocol aligned with international and national recommendations. Methods: A systematic review of current guidelines and studies was conducted to assess vaccination strategies in HCT recipients. The analysis included the timing of vaccine administration, factors influencing efficacy, and contraindications. Recommendations for pre- and post-transplant vaccination schedules were synthesised, specifically for graft-versus-host disease (GVHD), immunosuppressive therapy, and hypogammaglobulinemia. Results: Vaccination is essential as specific immunity is often lost after HCT. Inactivated vaccines are recommended to commence three months post-transplant, including influenza, COVID-19, and pneumococcal vaccines. Live attenuated vaccines remain contraindicated for at least two years post-transplant and in patients with ongoing GVHD or immunosuppressive therapy. Factors such as GVHD and immunosuppressive treatments significantly impact vaccine timing and efficacy. The review also underscores the importance of pre-transplant vaccinations and ensuring that patients' close contacts are adequately immunised to reduce transmission risks. Conclusions: Implementing a structured vaccination protocol post-HCT is critical to improving patient outcomes. Timely and effective vaccination strategies can mitigate infection risks while addressing individual patient factors such as GVHD and immunosuppression. This review highlights the need for tailored vaccination approaches to optimize immune reconstitution in HCT recipients. [ABSTRACT FROM AUTHOR]

Background: The development of effective and safe vaccines and their timely delivery to the public play a crucial role in preventing and managing infectious diseases. Many vaccines have been produced and distributed globally to prevent COVID-19 infection. However, establishing effective vaccine development platforms and evaluating their safety and immunogenicity remains critical to increasing health security, especially in developing countries. Objectives: Therefore, we developed a local subunit vaccine candidate, RENOVAC, and reported its toxicity and immunogenicity profile in animal models. Methods: First, the synthetic gene-coding tandem RBD linked with the GS linker was cloned into the expression vector and expressed in CHO cells. The protein was then purified and filter sterilized, and 10 µg/dose and 25 µg/dose formulations were finally examined for the 14-day repeated dose toxicity followed by the immunogenic profile in preclinical studies. Results: When administered to Sprague Dawley rats by intramuscular route, the vaccine was well tolerated up to and including the dose of 25 µg/animal, and no toxicologically adverse changes were noted. The observed change in weight of the thymus and spleen might be related to the immunological response to the vaccine. The dimer RBD vaccine demonstrated the ability to generate high levels of specific immunoglobulins (IGs) and neutralization antibodies (NAbs). Finally, changes in the amounts of specific T cells and cytokines after vaccination suggested that the vaccine mainly triggers an immune response by activating CD4+ Th2-cells, which then activate B-cells to provide humoral immunity. Conclusions: The study suggests that, based on its reliable immunogenicity and acceptable safety, the vaccine can be further directed for clinical trials. [ABSTRACT FROM AUTHOR]

Background and Objectives: Given that COVID-19 vaccination is a relatively recent development, particularly when compared to immunisation against other diseases, it is crucial to assess its efficacy in vaccinated populations. This literature review analysed studies that monitored antibody titres against SARS-CoV-2 in healthcare workers who received COVID-19 vaccines. Methods: Using the PICO (Population, Intervention, Comparators, Outcomes) model recommended in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines we included 43 publications which analyse antibody dynamics following primary vaccination, the effects of booster doses, and the influence of factors such as COVID-19C infection, age, and sex on antibody kinetics. Results: All the studies demonstrated a strong immunogenic response to the vaccines. Re-gardless of the vaccine used, over 95% of the pre-vaccination seronegative population be-came seropositive in all studies. Depending on the sampling intervals provided by the re-searchers, antibody levels were quantitatively highest during the first three months after vaccination, but levels inevitably declined over time. The monthly decline in antibodies observed in all these studies highlighted the necessity for booster doses. Studies analysing the impact of revaccination on antibody dynamics have confirmed that revaccination is an effective tool to boost humoral immunity against SARS-CoV-2. An-tibodies appear to persist for a longer period of time after revaccination, although they are subject to similar factors influencing antibody dynamics, such as age, comorbidities, and exposure to COVID-19. In addition, heterogeneous revaccination strategies have been shown to be more effective than homogeneous revaccination. Conclusions: Our review demonstrated that antibody levels against SARS-CoV-2 inevitably decline after vaccination, leaving the question of ongoing booster strategies open. The studies reviewed provided evidence of the effectiveness of booster vaccination, despite differences in age, sex, and prior COVID-19 infection. This suggests that repeated vaccination remains a highly effective method for mitigating the continued threat posed by COVID-19. [ABSTRACT FROM AUTHOR]

Background/Objective: Duck virus hepatitis (DVH), caused by duck hepatitis A virus (DHAV), poses significant challenges to duck farming due to high mortality rates in young ducklings. Despite the widespread use of live attenuated vaccines, the genetic diversity within DHAV strains has diminished their cross-protection efficacy. This study aimed to evaluate the cross-protective efficacy of current DHAV-1 and DHAV-3 vaccines against genetically divergent wild strains. Methods: Phylogenetic analyses of the VP1 genes from DHAV-1 and DHAV-3 were conducted. Both DHAV-1 and DHAV-3 vaccines were tested in ducklings, with and without maternal-derived antibodies (MDA), through challenge trials with homologous and heterologous strains. Results: In the phylogenetic analysis, compared to vaccine strains, DHAV-1 and DHAV-3 field variant strains were classified into different genotypes. In ducklings without MDA, the DHAV-1 vaccine provided 60% survival against homologous strains by 2 days post-vaccination (DPV) and complete protection by 4 DPV, while survival rates against heterologous strains ranged from 40 to 60%. In ducklings with MDA, the DHAV-1 vaccine provided full protection with an additional vaccination for day-old ducklings against heterologous strains. The DHAV-3 vaccine conferred complete protection against both homologous and heterologous strains by 2 DPV, regardless of MDA presence. Conclusions: The DHAV-3 vaccine demonstrated robust cross-protection across genotypes, while the DHAV-1 vaccine showed limitations against genetically divergent strains. These findings highlight the necessity for genotype-matched vaccines and optimized immunization strategies to enhance protection against evolving DHAV field strains. [ABSTRACT FROM AUTHOR]

Background/Objectives: Healthcare professionals (HCPs) hold significant influence over public attitudes toward vaccinations. Studies suggest that HCPs are hesitant towards the coronavirus disease 2019 (COVID-19) vaccines. This hesitancy could lead to lower vaccination rates in the community. Therefore, this scoping review aimed to assess the extent of hesitancy towards COVID-19 booster doses among HCPs and identify the associated factors. Methods: A comprehensive search was conducted in the PubMed and Scopus databases from April to August 2024, using keywords related to COVID-19, vaccine hesitancy, HCPs, and booster vaccination. Studies that had been peer-reviewed, published in English after 2022, and focused on the hesitancy of the COVID-19 booster dose hesitancy among HCPs were included. Out of the 6703 studies screened, 24 studies were included. Results: Most of the HCPs have received their initial series of COVID-19 vaccinations. However, there is a lower rate of uptake for booster doses, with hesitancy rates ranging from 12% to 66.5%. Hesitancy rates varied significantly across continents, with Asia, Africa, and Europe ranging from 19.7% to 66.5%, 27% to 46.1%, 14% to 60.2%, respectively. Hesitancy was reported to be influenced by various factors, including concerns about vaccine safety, necessity, and effectiveness of these vaccines. In addition, the hesitancy regarding booster doses was also found to be influenced by factors like age, gender, profession, and previous COVID-19. Physicians, nurses, and pharmacists exhibited vaccine hesitancy rates ranging from 12.8% to 43.7%, 26% to 37%, and 26% to 34.6%, respectively. Conclusions: Our review underscores the hesitancy among HCPs towards receiving booster doses across countries around the world and explores the underlying factors. These findings provide valuable insights for the design of future pandemic vaccination programs. [ABSTRACT FROM AUTHOR]

Background/Objectives: Since 2022, outbreaks of monkeypox have raised widespread concern and have been declared a public health emergency of international concern by the World Health Organization. There is an urgent need to develop a safe and effective vaccine against the monkeypox virus (MPXV). Recombinant protein vaccines play a significant role in the prevention of infectious diseases due to their high safety and efficacy. Methods: We used the A29, E8, M1, A35, and B6 proteins of MPXV as candidate antigens to generate a panel of multi-component MPXV vaccine candidates, which were administered subcutaneously to immunize mice. Results: The results showed that the vaccine candidates Mix-AEM, Mix-AEMA, Mix-AEMB, and Mix-AEMAB effectively elicited strong neutralizing antibody responses and demonstrated significant protection against vaccinia virus (VACV) infection in a murine model. The vaccine candidate Mix-AEM induced significantly higher levels of neutralizing antibodies, cellular immunity capacity, and virus clearance compared to the vaccine candidate Mix-AE (lacking M1). Single-component immunization showed that M1 induced higher levels of neutralizing antibodies than A29 and E8. These results indicated that M1 is a critical and essential antigen in the MPXV vaccine. The number of cells secreting IFN-γ was significantly increased in the Mix-AEMA and Mix-AEMAB groups compared to the A35-deficient vaccine candidates, demonstrating the important role of A35 in inducing IFN-γ secreting. In addition, the neutralizing antibodies induced by these multi-component vaccine candidates were maintained at high levels six months after the third immunization. Conclusions: In summary, this study lays the groundwork for combining antigens to develop multi-component subunit vaccines. [ABSTRACT FROM AUTHOR]

Background/objectives: Coronavirus-19 (COVID-19) vaccines represent a significant milestone in the fight against coronavirus disease. Ongoing post-marketing surveillance and research are crucial for ensuring vaccine safety and effectiveness, aiding public health planning. Methods: Our retrospective cohort study included Albertans five years and older and vaccinated with at least one dose of an approved COVID-19 vaccine between 14 December 2020 and 30 April 2022. This epidemiological study aimed to determine the incidence of reported adverse events following immunization (AEFI) in Alberta and identify associated risk factors. Results: The study included 3,527,106 vaccinated Albertans who met the study inclusion criteria. A total of 2541 individuals (72.0 per 100,000) reported an AEFI, with 2759 adverse events, most of which occurred following the first dose of vaccine and within the first week post-vaccination. Of these, 70.4% were female, and the highest incidence was in the 35–54 age group. Given that mRNA vaccines were predominantly administered across Canada, we report AEFI rates (per 100,000 doses) for the mRNA vaccine brands at 27.7 for Pfizer and 40.7 for Moderna. Allergic events were the most frequently reported AEFI, followed by adenopathy. Logistic regression analysis indicated that sex (with females at higher risk), presence of comorbidities, days to symptom onset, vaccine type (mRNA vs. mixed doses), and the number of doses were significant factors associated with an AEFI event. Conclusions: Our study provides valuable information to guide policies surrounding COVID-19 vaccination. While the risk of serious adverse events was low in the population-based sample, further research is warranted to identify and investigate other possible risk factors that are still unknown. [ABSTRACT FROM AUTHOR]

Background/Objectives: Orthoebolaviruses and orthomarburgviruses are filoviruses that can cause viral hemorrhagic fever and significant morbidity and mortality in humans. The evaluation and deployment of vaccines to prevent and control Ebola and Marburg outbreaks must be informed by an understanding of the transmission and natural history of the causative infections, but little is known about the burden of asymptomatic infection or undiagnosed disease. This systematic review of the published literature examined the seroprevalence of antibodies to orthoebolaviruses and orthomarburgviruses in sub-Saharan Africa. Methods: The review protocol was registered on PROSPERO (ID: CRD42023415358) and previously published. Eighty-seven articles describing 85 studies were included, of which seventy-six measured antibodies to orthoebolaviruses and forty-one measured antibodies to orthomarburgviruses. Results: The results highlight three central findings that may have implications for vaccine development and deployment. First, substantial antibody seropositivity to Ebola virus (EBOV) and Sudan virus (SUDV) was observed in populations from outbreak-affected areas (≤33% seroprevalence among general populations; ≤41% seroprevalence among healthcare workers and close contacts of disease cases). Second, antibody seropositivity to EBOV, SUDV, and Marburg virus (MARV) was observed among populations from areas without reported outbreaks, with seroprevalence ranging from <1 to 21%. Third, in Central and East Africa, MARV antibody seroprevalence was substantially lower than EBOV or SUDV antibody seroprevalence, even in outbreak-affected areas and in populations at a moderate or high risk of infection (with MARV seroprevalence mostly ranging from 0 to 3%). Conclusions: Whilst gaps remain in our understanding of the significance of antibody seropositivity in some settings and contexts, these findings may be important in considering target indications for novel filovirus vaccines, in defining study designs and strategies for demonstrating vaccine efficacy or effectiveness, and in planning and evaluating vaccine deployment strategies to prevent and control outbreaks. [ABSTRACT FROM AUTHOR]

Plague, caused by Yersinia pestis, poses a public health threat not only due to sporadic outbreaks across the globe but also due to its potential as a biothreat agent. Ironically, among the seven deadliest pandemics in global history, three were caused by Y. pestis. Pneumonic plague, the more contagious and severe form of the disease, is difficult to contain, requiring either prophylactic antibiotic treatment or vaccination. However, no vaccine (live attenuated or subunit) is currently approved by the Food and Drug Administration, requiring rigorous preclinical studies in different animal models, thus forming the basis of this study. Objectives: The aim of this study was to evaluate the efficacy and immune responses of two live attenuated vaccines (LAVs), LMA and LMP, either alone or in combination with a trivalent adenoviral vector-based vaccine (Ad5-YFV), in IL-17A-depleted and IgG control mice by using an anti-IL-17A monoclonal antibody (mAb) or its matched isotype IgG, respectively. Methods: IL-17A mAb or IgG isotype control was administered to mice twice per week to their respective groups during the course of immunization. Serum, spleens, and broncho-alveolar lavage fluid (BALF) were collected for assessing immunological responses, and another cohort of mice was intranasally challenged with a lethal dose of parental Y. pestis CO92. Results: Robust humoral and cellular immune responses followed by complete protection were observed in all vaccinated animals against highly lethal intranasal challenge doses of parental Y. pestis CO92. Serum IgG titers to YscF and overall mucosal IgA titers to all three antigens of the Ad5-YFV vaccine were significantly lower, with slightly reduced serum LcrV-neutralizing antibodies when IL-17A was depleted compared to IgG control animals during the course of immunization. A remarkable reduction in Th1 (IFNγ or IL-2) and Th17 cell populations was observed in IL-17A-depleted mice compared to IgG controls in response to vaccination. On the other hand, B cell activities in germinal centers, overall activated antigen-specific T cells, and memory B and T cells remained at comparable levels in both vaccinated IL-17A-depleted and IgG control mice. Conclusions: These data demonstrated the effectiveness of our vaccines even under the reduced levels of both Th1 and Th17 responses and thus should be suitable for those individuals associated with certain immune deficiencies. [ABSTRACT FROM AUTHOR]

Human papillomavirus (HPV) is the most common sexually transmitted infection and plays a significant role in cervical, penile, anal, vaginal, vulvar, and oropharyngeal cancers as well as non-cancerous genital warts and genital dysplasia. In the United States, there are approximately 46,000 new HPV-related cancers a year. There is an effective vaccine to prevent over 90% of these cancers and other HPV-related diseases; however, those that are aged 18–26 have the lowest vaccine rates among eligible age groups. The objective of this study was to examine student knowledge and perceptions about HPV vaccine hesitancy in university students and their notions of barriers and facilitators for HPV vaccine uptake. We aimed to identify components for an evidence-based community-oriented educational intervention to increase HPV vaccination uptake. The researchers recorded 10 focus groups featuring students from a Northeastern United States university, aged 18–26, which were analyzed using grounded theory and inductive thematic analysis to identify recurring themes. The participants mentioned many barriers and facilitators for attaining the HPV vaccine, with health literacy being prominent for both. They demonstrated some knowledge of what HPV is and ways to avoid it. They also expressed a desire for further information and felt that the way in which this information is presented to the public is vital for increasing vaccine uptake and designing future interventions. In order to increase HPV vaccination rates in the general population and overcome barriers such as family, religious, and cultural values, it is important to emphasize the link between HPV and cancer and its preventative benefits. [ABSTRACT FROM AUTHOR]

Background: The emergence of new COVID-19 variants continues to affect healthcare workers (HCWs) and vulnerable populations in the post-pandemic era. This study aims to assess the willingness, perceptions, and factors associated with booster COVID-19 vaccine uptake in this context. Methods: A cross-sectional study was conducted between October 2023 and May 2024 among Thai adults (>20 years old) in Chiang Mai, Northern Thailand. Participants included HCWs and patients with chronic medical conditions. People who had received a monovalent XBB-derived booster vaccine were excluded. Results: Data related to a total of 811 participants were analyzed, with 328 from the vulnerable group and 483 HCWs. Willingness to receive the booster was similar in both groups (43.3% in HCWs, 45.0% in the vulnerable group). Low-risk perception (59.6%–83.5%), minimal impact on daily life (60.4%–62.9%), and doubts about booster efficacy (75.9%–81.4%) were prevalent negative thoughts toward the booster. Having received a flu vaccine (aOR 2.1), concerns about the impact on life of COVID-19 (aOR 1.8), and beliefs in booster safety (aOR 1.8) and vaccine effectiveness against severe disease (aOR 2.7) were associated with increased willingness. Conclusions: Only 44% of participants were willing to receive a COVID-19 booster. Policymakers can use these insights to develop strategies to increase vaccine uptake in the post-pandemic era. [ABSTRACT FROM AUTHOR]

Background/Objectives: Tetanus is a serious, non-contagious infection caused by Clostridium tetani, which remains a global health threat despite the availability of an effective vaccine. The current state of immunization for agricultural workers in Italy reveals significant disparities, reflecting a non-homogeneous distribution of vaccination coverage across regions and subgroups. The aim of the study was to investigate the prevalence of tetanus antibodies in a cohort of agricultural workers in Eastern Sicily in order to evaluate possible public health strategies for improving vaccination coverage. Methods: This observational retrospective study assessed tetanus immunization coverage in agricultural workers in Eastern Sicily during the period from 2012–2022. Results: A total of 1143 workers participated, of which 71% (n = 871) had protective tetanus antitoxin levels. Of the 835 vaccinated workers, 9% were not immune, while 19% of those who were not vaccinated or did not recall their vaccination history were immune. Significant gaps in vaccination were noted, particularly among non-European workers, with only 23% vaccinated compared to 89% of European workers. Additionally, vaccination rates were higher in those born after 1963, when vaccination became mandatory. Conclusions: The results underscore the need for targeted vaccination strategies, especially for older and migrant workers, as well as the importance of workplace immunization programs led by occupational physicians. Improving vaccination coverage among agricultural workers is essential for preventing tetanus infections in high-risk agricultural populations. [ABSTRACT FROM AUTHOR]

Background: Cervical cancer is associated with persistent infection of high-risk human papillomaviruses (HPVs). Prophylactic HPV vaccines have been recommended and have significant efficacy in preventing cervical cancer. Multivalent HPV vaccines have a better preventative effect on HPV-related diseases. However, there is currently only one nine-valent HPV vaccine on the market: Gardasil® 9. The development of new HPV vaccines is still urgent in order to achieve the goal of eliminating cervical cancer as proposed by the WHO. Methods: In this study, we developed a nine-valent recombinant HPV virus-like particle (VLP) vaccine (HPV-9 vaccine) containing HPV type 6, 11, 16, 18, 31, 33, 45, 52, and 58 antigens, with an adjuvant of aluminum phosphate (AlPO4). The type-specific L1 proteins were recombinantly expressed using Pichia pastoris, followed by self-assembly into VLPs. Immunogenicity studies of the HPV-9 vaccine were performed using rodents (mice and rats) and non-human primates (macaques) as animal models. Results: Immunogenicity studies showed that the HPV-9 vaccine is able to elicit a robust and long-lasting neutralizing antibody response in rodents (mice and rats) and non-human primates (cynomolgus macaque) models. The HPV-9 vaccine shows immunogenicity comparable to that of Walrinvax® and Gardasil® 9. Conclusions: In summary, this study provides a comprehensive investigation of the immunogenicity of the HPV-9 vaccine, including its immune persistence. These findings, derived from using models of diverse animal species, contribute valuable insights into the potential efficacy of the vaccine candidate in clinical settings. [ABSTRACT FROM AUTHOR]

Background/Objectives: COVID-19 is an infectious disease whose prevention is significantly aided by vaccination, which reduces both case severity and mortality. Despite the safety and efficacy of vaccines, acceptance is not universal, and understanding of the factors influencing vaccination decisions and hesitancy remains limited. This review aims to identify and analyze studies addressing two key questions: what influences the decision to vaccinate and what factors are associated with vaccine hesitancy. Methods: This systematic review was conducted following the PRISMA guidelines. Data collection utilized descriptors related to vaccine adherence and hesitancy, based on the PEO strategy of the Joanna Briggs Institute (JBI). Searches were conducted in Embase, Scopus, PubMed, Lilacs, and Web of Science, focusing on publications from 2021, the year the first COVID-19 vaccine was approved. After excluding duplicates and selecting articles based on eligibility criteria, the analysis involved data extraction and methodological quality assessment using JBI tools. Results: A total of 5268 publications were identified, with 30 included in this study. Factors associated with vaccine hesitancy included low education levels, social media influence, confidence in vaccine safety, and fear of side effects. In contrast, factors linked to vaccine acceptance included higher education, higher income, older age, and existing comorbidities. Conclusions: The findings highlight the urgent need for targeted health communication and education strategies, particularly for vulnerable groups. Public health policies should incorporate these factors to enhance vaccination adherence and build public confidence in vaccine safety, which is essential for mitigating future health emergencies. [ABSTRACT FROM AUTHOR]

Background/Objectives: Respiratory syncytial virus (RSV) is the leading cause of severe respiratory disease in infants worldwide. Maternal immunization to protect younger infants is supported by evidence that virus-neutralizing antibodies, which are efficiently transferred across the placenta from mother to fetus, are a primary immune mediator of protection. In maternal RSV vaccine studies, estimates of correlates of protection are elusive because many factors of maternal–fetal immunobiology and disease characteristics must be considered for the estimates. Methods: We developed statistical models that aims to predict vaccine efficacy (VE) in infants following maternal immunization by including quantifiable covariates of the antibody titer distribution of the mother (pre- and post-immunization), the transplacental transfer ratio of IgG antibodies, the rate of antibody decay, and RSV disease incidence rate, all of which are season- and time-dependent and vary by infant age. Result: Our model shows that integrating the lower respiratory tract disease risk based on infant airway diameter and associated airway resistance is critical to appropriately model predicted infant VE. The VE predictions by our models, which preceded maternal RSV prefusion F vaccine efficacy trial primary readouts, closely align with the VE outcomes of these field studies. Conclusion: Our models successfully predicted VE of the RSV maternal vaccines and have potential use in modeling the clinical trial out-comes of other respiratory disease vaccines where maternal antibodies play a role in the protection of newborns. [ABSTRACT FROM AUTHOR]

Outbreaks of avian pathogens such as Newcastle disease virus, avian influenza virus, and salmonella have a major impact on economies and food security worldwide. Some pathogens also pose a significant zoonotic potential, especially avian influenza viruses. Vaccination plays a key role in controlling many poultry diseases, and there are many vaccines licenced in the United Kingdom for diseases of poultry caused by viruses, bacteria, and parasites. However, these vaccines often do not provide complete protection and can cause unwanted side effects. Several factors affect the potency of poultry vaccines, including the type of vaccination used, the mechanism of delivery, and the use of adjuvants. Advancements in technology have led to the study and development of novel vaccines and vaccine adjuvants for use in poultry. These induce stronger immune responses compared with current vaccine technology and have the potential to protect against multiple poultry diseases. This review aims to discuss the existing poultry vaccine technology; the effect of delivery mechanisms on vaccine efficacy; the use of current and novel adjuvants; the ability to target antigens to antigen-presenting cells; and the use of probiotics, multivalent vaccines, and nanotechnology to enhance the potency of poultry vaccines. [ABSTRACT FROM AUTHOR]

The recent resurgence of mpox highlights the urgent need for rethinking vaccination strategies globally, underscored by the painful memories of past public health crises where delayed responses and inequitable vaccine distribution exacerbated the spread of infectious diseases. The inaugural APIC-ADVA Asia Pacific Summit on Infectious Diseases and Immunization, themed "Vaccination for All: Access, Confidence and Equity (ACE)", was held in Singapore from 31 October to 1 November 2023 in an attempt to present best practices and hard-won insights from battling COVID-19 and other pandemics in the Asia-Pacific region. This summit was co-convened by the Asia-Pacific Immunization Coalition (APIC) and Asia Dengue Voice and Action (ADVA). Local, regional, and international experts from academia, research and representatives from the Ministries of Health, the World Health Organization (WHO), and the International Vaccine Institute (IVI) participated in the 2 day summit. With more than 230 speakers and delegates from over 15 countries, and 4 symposia over 2 full days, the first APIC-ADVA Asia Pacific Summit on Infectious Diseases and Immunization highlighted critical issues affecting vaccine access, confidence, and equity, and emphasized the importance of safeguarding the world from existing infections and future pandemics through immunization. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) remains a leading cause of morbidity and mortality worldwide, necessitating the development of more effective vaccines. Nanoparticle-based adjuvants represent a promising approach to enhancing tuberculosis vaccine efficacy. This review focuses on the advantages of nanoparticulate-loaded vaccines, emphasizing their ability to improve antigen delivery, safety, and immunogenicity. We discuss the various types of nanoparticles and their unique physicochemical properties that contribute to improved antigen delivery and sustained immune activation. Additionally, we highlight the advantages of nanoparticle-based adjuvants in inducing strong cellular and humoral immunity, enhancing vaccine stability, and reducing adverse effects. Finally, we address current challenges and future perspectives in the application of these novel adjuvants, emphasizing their potential to transform TB vaccine strategies and ultimately contribute to better global health outcomes. [ABSTRACT FROM AUTHOR]

Background/Objectives: HBV infections can lead to serious liver complications that can have fatal consequences. In 2022, around 1.1 million individuals died from HBV-related cirrhosis and hepatocellular carcinoma. Vaccines allow us to save more than 2.5 million lives each year; however, up to 10% of vaccinated individuals may not develop sufficient protective antibody levels. The aim of this study was to investigate the epigenetic drift in the response to HBV vaccine in isolated B cells. Methods: Epigenetic drift was measured by counting rare DNA methylation variants. These epivariants were detected in epigenome-wide data collected from isolated B cell samples from 41 responders and 30 non-responders (age range 22–62 years) to vaccination against HBV. Results: We found an accumulation of epivariants in the NR group, with a significant increase in hyper-methylated aberrations. We identified the chromosomes (1, 3, 11, 12, and 14) and genes (e.g., RUSC1_AS1 or TROVE2) particularly enriched in epivariants in NRs. The literature search and pathway analysis indicate that such genes are involved in the correct functioning of the immune system. Moreover, we observed a correlation between epigenetic drift and DNA methylation entropy in the male population of the cohort. Finally, we confirmed the correlation between epivariant loads and age-related epigenetic clocks. Conclusions: Our findings support the idea that an age-related derangement of the epigenetic architecture is involved in unresponsiveness to the HBV vaccine. Furthermore, the overall results highlight the interconnection between various epigenetic dynamics (such as drift, clocks, and entropy), although these interconnections seem not to be involved in the altered immunological activity. [ABSTRACT FROM AUTHOR]

Background/Objectives: Considering the large number of candidates in vaccine-testing studies against different pathogens and the amount of time spent in the preclinical and clinical trials, there is a pressing need to develop an improved in vivo system to quickly screen vaccine candidates. The model of a polyester–polyurethane sponge implant provides a rapid analysis of the specific stimulus–response, allowing the study of a compartmentalized microenvironment. The sponge implant's defined measurements were standardized as a compartment to assess the immune response triggered by the vaccinal antigen. The LBSap vaccine (composed of Leishmania braziliensis antigens associated with saponin adjuvant) was used in the sponge model to assess the antigen-specific immunological biomarker, including memory generation after initial contact with the antigen. Methods: Mice strains (Swiss, BALB/c, and C57BL/6) were previously immunized using LBSap vaccine, followed by an antigenic booster performed inside the sponge implant. The sponge implants were assessed after 72 h, and the immune response pattern was analyzed according to leukocyte immunophenotyping and cytokine production. Results: After LBSap vaccination, the innate immune response of the antigenic booster in the sponge implants demonstrated higher levels in the Ly+ neutrophils and CD11c+ dendritic cells with reduced numbers of F4/80+ macrophages. Moreover, the adaptive immune response in Swiss mice demonstrated a high CD3+CD4+ T-cell frequency, consisting of an effector memory component, in addition to a cytoxicity response (CD3+CD8+ T cells), displaying the central memory biomarker. The major cell surface biomarker in the BALB/c mice strain was related to CD3+CD4+ effector memory, while the increased CD3+CD8+ effector memory was highlighted in C57/BL6. The cytokine profile was more inflammatory in Swiss mice, with the highest levels of IL-6, TNF, IFN-g, and IL-17, while the same cytokine was observed in in C57BL/6 yet modulated by enhanced IL-10 levels. Similar to Swiss mice, BALB/c mice triggered an inflammatory environment after the antigenic booster in the sponge implant with the increased levels in the ILL-6, TNF, and IFN-g. Conclusions: The findings emphasized the impact of genetic background on the populations engaged in immune responses, suggesting that this model can be utilized to enhance and track both innate and adaptive immune responses in vaccine candidates. Consequently, these results may inform the selection of the most suitable experimental model for biomolecule testing, taking into account how the unique characteristics of each mouse strain affect the immune response dynamics. [ABSTRACT FROM AUTHOR]

Celiac disease (CD) is an autoimmune disorder caused by gluten intake in genetically predisposed individuals. This article provides an overview of the available data on the risks of infectious diseases and the mechanisms involved in CD, including a detailed analysis of vaccine efficacy, immunogenicity, and safety. The published articles were retrieved from the PubMed database using the terms "celiac disease", "efficacy", "hyposplenism", "immune response", "infections", "immunization", "immunogenicity", "safety", "vaccination", and "vaccine". CD can be associated with several autoimmune diseases, including selective immunoglobulin A deficiency (SIgAD), altered mucosal permeability, and hyposplenism. These conditions entail an increased risk of infections, which can be prevented by targeted vaccinations, although specific recommendations on immunization practices for subjects with CD have not been released. Regarding vaccinations, the immune response to the Hepatitis B virus (HBV) vaccine can be impaired in patients with CD; therefore, proposed strategies to elicit and maintain protective specific antibody titers are summarized. For patients with conditions that put them at risk of infections, vaccinations against Pneumococcus and other encapsulated bacteria should be recommended. Based on the available evidence, the Rotavirus vaccine offered to children could be useful in preventing CD in at-risk subjects. Overall, except for the HBV vaccine, vaccine efficacy in patients with CD is comparable to that in the general population, and no safety concerns have arisen. [ABSTRACT FROM AUTHOR]

Objectives: Although bluetongue is not a contagious disease, it is easily transmitted and spread by appropriate insect vectors, causing great economic damage. Climate change has led to the fact that vectors and diseases have spread to the top of Northern Europe, causing great economic losses in livestock production. An even greater problem is controlling the disease, because numerous species of domestic and wild ruminants are susceptible to bluetongue. The most effective tool against bluetongue disease is vaccination. Methods: Our goal was to carry out laboratory tests of the starting material and the finished product of the candidate inactivated vaccine against BTV4, and to comment on the obtained laboratory results and the results of previously performed clinical studies. There is no ideal vaccine against the bluetongue virus (BTV) due to the serotype diversity of its strains. Thus, there is a need for a vaccine for at least 24 clinically significant serotypes. Sometimes, it is difficult to obtain the desired amount of vaccine against a defined serotype on the market, and this has led to the need for a new vaccine against bluetongue disease. In this study, we tested an experimental inactivated vaccine against BTV4. The master seed BTV4 was examined and characterized by sequencing. Results: The candidate BTV4 vaccine induced the onset of immunity at the latest at day 21 after the application of the first dose in more than 80% of the vaccinated individuals, while the ELISA test detected specific antibodies against BTV for more than a year. Along with our laboratory results, the preliminary results of safety and efficacy trials are also presented. Conclusions: The side effects of this inactivated BTV4 vaccine are within the limits of permissible local reactions without generalized changes in the health status, while the serology and challenge test leads to the conclusion that this vaccine against BTV4 protects a high percentage of vaccinated individuals against BTV4 or causes a significant reduction in the intensity and duration of the clinical signs in the vaccinated sheep. Based on the trial results, the new vaccine has given encouraging results in terms of quality, safety, and preliminary efficacy tests. Thus, we believe that a new vaccine against BTV is on the horizon. [ABSTRACT FROM AUTHOR]

Background: The global COVID-19 pandemic has resulted in approximately 7 million deaths and a historic vaccination effort, with over 13.6 billion doses administered. Despite this, understanding of immune responses in vulnerable populations, such as transplant recipients (TR) and hemodialysis patients (HD), remains limited, especially outside the US and Europe. Methods: To address this gap, we analyzed blood samples and deidentified data from the Instituto Nacional de Coordinación de Trasplante (INCORT) in The Dominican Republic, measuring antibody levels to SARS-CoV-2 post-infection and vaccination with BNT162b2 (Pfizer-BioNTech) and Sinovac-CoronaVac (Sinovac) in TR, HD, and healthy controls (CO). Using a fluorescent multiplex assay (mPlex-CoV) and mixed-effects modeling, we assessed variations in anti-S, anti-RBD, and anti-N IgG antibodies. Results: The results indicate that the CO group experienced an early peak in anti-S and anti-RBD antibodies, followed by stabilization. In contrast, the TR and HD groups showed a slower, gradual increase in antibodies. Despite fluctuations in the HD group, both the TR and HD groups maintained high anti-S and anti-RBD IgG levels, indicating a back-boosting effect from vaccination. However, elevated anti-N IgG levels in the TR and HD groups suggest potential reinfections. Additionally, prior SARS-CoV-2 infection led to higher anti-S IgG levels, with BNT162b2 associated with higher anti-S IgG and CoronaVac associated with higher anti-N IgG levels. Conclusion: These findings highlight the variability in antibody responses and the need for targeted public health strategies to diverse immunological profiles. [ABSTRACT FROM AUTHOR]

Background: Pigeon paramyxovirus type 1 (PPMV-1) is a significant pathogen affecting pigeon populations globally. The commonly used La Sota vaccine provides limited protection due to antigenic divergence from circulating PPMV-1 strains. An antigenically matched vaccine is needed to address this challenge. Methods: An attenuated aTJ strain was developed through reverse genetics by modifying the F protein cleavage site of the virulent TJ-WT strain. Pigeons were immunized twice with the aTJ strain via eyedrop and intranasal routes, followed by a challenge with a virulent PPMV-1 strain ten days after the booster immunization. Results: The attenuated aTJ strain induced robust serum antibody titers post-booster immunization, and vaccinated pigeons showed strong protection upon challenge, with significantly reduced morbidity, mortality, and viral shedding compared to controls. Conclusions: These findings suggest that the aTJ strain is a promising candidate for the promotion of PPMV-1 prevention and control, emphasizing the importance of antigenic matching in optimizing vaccine efficacy. [ABSTRACT FROM AUTHOR]

Background/Objectives: The COVID-19 pandemic has significantly impacted global health, with varying vaccine effectiveness (VE) across different regions and vaccine platforms. In Africa, where vaccination rates are relatively low, inactivated vaccines like BBIP-CorV (Sinopharm) and Coronovac (Sinovac) have been widely used. This study evaluated the real-world effectiveness of licensed inactivated COVID-19 vaccines in Zimbabwe during a period dominated by Omicron variants. Methods: We conducted a prospective, test-negative, case–control study among symptomatic adults across six Zimbabwean provinces from November 2022 to October 2023. Participants were categorized based on vaccination status, and nasopharyngeal swabs were collected for SARS-CoV-2 PCR testing. Vaccine effectiveness was assessed using conditional logistic regression, adjusting for various covariates such as age, sex, and comorbidities. Results: Among 5175 participants, 701 tested positive for SARS-CoV-2 and 4474 tested negative. The overall adjusted VE against symptomatic COVID-19 was 31% (95% CI: 5.3–49.7%) among verified vaccinated individuals. Boosted individuals demonstrated a higher VE of 59.8% (95% CI: 40.3–72.9%). VE decreased significantly to 24% (95% CI: −4.1–44.8%) in individuals vaccinated over a year prior. Similar VE was observed for BBIP-CorV (36.8%, 95% CI: 11.4–54.9%) and Coronovac (38.1%, 95% CI: 16.3–54.2%). Conclusions: This study indicates modest protection from inactivated COVID-19 vaccines against symptomatic Omicron infection, with significant enhancement following booster doses. These findings highlight the need for continued vaccine evaluation, particularly in resource-limited settings, to inform public health strategies and optimize vaccination programs. [ABSTRACT FROM AUTHOR]

Between 2013 and 2016, the A/H1N1pdm09 component of the live attenuated influenza vaccine (LAIV) produced instances of lower-than-expected vaccine effectiveness. Standard pre-clinical ferret models, using a human-like vaccine dose and focusing on antigenic match to circulating wildtype (wt) strains, were unable to predict these fluctuations. By optimising the vaccine dose and utilising clinically relevant endpoints, we aimed to develop a ferret efficacy model able to reproduce clinical observations. Ferrets were intranasally vaccinated with 4 Log10 FFU/animal (1000-fold reduction compared to clinical dose) of seven historical LAIV formulations with known (19–90%) H1N1 vaccine efficacy or effectiveness (VE). Following homologous H1N1 wt virus challenge, protection was assessed based on primary endpoints of wt virus shedding in the upper respiratory tract and the development of fever. LAIV formulations with high (82–90%) H1N1 VE provided significant protection from wt challenge, while formulations with reduced (19–32%) VE tended not to provide significant protection. The strongest correlation observed was between reduction in wt shedding and VE (R2 = 0.75). Conversely, serum immunogenicity following vaccination was not a reliable indicator of protection (R2 = 0.37). This demonstrated that, by optimisation of the vaccine dose and the use of non-serological, clinically relevant protection endpoints, the ferret model could successfully translate clinical H1N1 LAIV VE data. [ABSTRACT FROM AUTHOR]

Background: European countries have included healthcare workers (HCWs) among priority groups for COVID-19 vaccination. We established a multi-country hospital network to measure the SARS-CoV-2 incidence and effectiveness of COVID-19 vaccines among HCWs against laboratory-confirmed SARS-CoV-2 infection. Methods: HCWs from 19 hospitals in 10 countries participated in a dynamic prospective cohort study, providing samples for SARS-CoV-2 testing at enrolment and during weekly/fortnightly follow-up. We measured the incidence during pre-Delta (2 May–6 September 2021), Delta (7 September–14 December 2021), and Omicron (15 December 2021–2 May 2023) waves. Using Cox regression, we measured the relative vaccine effectiveness (rVE) of the first COVID-19 booster dose versus primary course alone during Delta and Omicron waves. Results: We included a total of 3015 HCWs. Participants were mostly female (2306; 79%), with a clinical role (2047; 68%), and had a median age of 44 years. The overall incidence of SARS-CoV-2 infection was 3.01/10,000 person-days during pre-Delta, 4.21/10,000 during Delta, and 23.20/10,000 during Omicron waves. rVE was 59% (95% CI: −25; 86) during Delta and 22% (1; 39) during Omicron waves. rVE was 51% (30; 65) 7–90 days after the first booster dose during the Omicron wave. Conclusions: The incidence of SARS-CoV-2 infection among HCWs was higher during the Omicron circulation period. The first COVID-19 vaccine booster provided additional protection against SARS-CoV-2 infection compared to primary course vaccination when recently vaccinated <90 days. This multi-country HCW cohort study addressing infection as the main outcome is crucial for informing public health interventions for HCWs. [ABSTRACT FROM AUTHOR]

Background/Objectives: Since its emergence in 2019, the rapid spread of SARS-CoV-2 led to the global pandemic. Recent large-scale dengue fever outbreaks overlapped with the COVID-19 pandemic, leading to increased cases of co-infection and posing severe public health risks. Accordingly, the development of effective combined SARS-CoV-2 and dengue virus (DENV) vaccines is necessary to control the spread and prevalence of both viruses. Methods: In this study, we designed Sindbis virus (SINV) replicon-based SARS-CoV-2 and DENV chimeric vaccines using two delivery strategies: DNA-launched self-replicating RNA replicon (DREP) and viral replicon particle (VRP) systems. Results: Cellular and animal experiments confirmed that the vaccines effectively produced viral proteins and elicited strong immunogenicity. These vaccines induced robust immune responses and neutralizing activity against live SARS-CoV-2, DENV1, and DENV2 viruses. In addition, passively transferred sera from BALB/c mice immunized with these vaccines into AG129 mice provided significant protection against lethal DENV2 challenge. The transferred sera protected the mice from physical symptoms, reduced viral loads in the kidney, spleen, liver, and intestine, and prevented DENV2-induced vascular leakage in these tissues. Conclusions: Therefore, combined vaccines based on the SINV replicon system are promising candidates for pandemic control. These results lay a foundation for further development of a safe and effective combination vaccine against SARS-CoV-2 and DENV. [ABSTRACT FROM AUTHOR]

Background: Human papillomavirus (HPV) persistent infection is a major pathogenic factor for HPV-related cancers, such as cervical cancer (CC), vaginal cancer, vulvar cancer, anal cancer, penile cancer, and head and neck cancer (HNC). Since the introduction of the world's first prophylactic HPV vaccine, there has been a decline in the incidence of HPV infections and associated cancers. This article reviews the latest literature on the research progress, efficacy, and safety of HPV vaccines for these cancers, providing a reference for HPV vaccination strategy. Methods: By utilizing databases such as PubMed, Google Scholar, CNKI, and Wanfang, we conducted a literature search on research papers related to HPV vaccines from 2014 to 2024, employing keywords such as "HPV", "HPV vaccine", "CC", "vaginal cancer", "vulvar cancer", "anal cancer", "penile cancer" and "HNC". Additionally, we reviewed the latest information available on official websites, including the World Health Organization (WHO). Based on the quality and relevance of the papers, we selected over 100 of the most representative articles for further summarization and analysis. Results: Vaccination against HPV can effectively block the transmission of the virus and prevent HPV-related cancers. Current studies have confirmed the efficacy and safety of prophylactic HPV vaccination. However, numerous challenges remain. The global vaccination rate for preventive vaccines remains low, particularly in low- and middle-income countries. Nonetheless, in the future, we can enhance the accessibility, affordability, and coverage of HPV vaccines by expanding the indications of already licensed vaccines, continuously developing new vaccines. Conclusions: The HPV vaccine is an extremely effective measure for the prevention and treatment of HPV-related cancers. Although there are many challenges in expanding the coverage of the HPV vaccine. It is believed that in the not-too-distant future, both prophylactic and therapeutic HPV vaccines will achieve commendable results. [ABSTRACT FROM AUTHOR]

Glycoconjugate vaccines have been effective in preventing numerous bacterial infectious diseases and have shown recent potential to treat cancers through active immunotherapy. Soluble polysaccharides elicit short-lasting immune responses and are usually covalently linked to immunogenic carrier proteins to enhance the antigen-specific immune response by stimulating T-cell-dependent mechanisms. Nonetheless, the conjugation of purified polysaccharides to carrier proteins complexifies vaccine production, and immunization with protein glycoconjugates can lead to the undesirable immunogenic interference of the carrier. Recently, the use of nanoparticles and nanoassemblies for the delivery of antigenic saccharides has gathered attention from the scientific community. Nanoparticles can be easily functionalized with a diversity of functionalities, including T-cell epitope, immunomodulator and synthetic saccharides, allowing for the modulation and polarization of the glycoantigen-specific immune response. Notably, the conjugation of glycan to nanoparticles protects the antigens from degradation and enhances their uptake by immune cells. Different types of nanoparticles, such as liposomes assembled from lipids, inorganic nanoparticles, virus-like particles and dendrimers, have been explored for glycovaccine design. The versatility of nanoparticles and their ability to induce robust immune responses make them attractive delivery platforms for antigenic saccharides. The present review aims at summarizing recent advancements in the use of nano-scaled systems for the delivery of synthetic glycoantigens. After briefly presenting the immunological mechanisms required to promote a robust immune response against antigenic saccharides, this review will offer an overview of the current trends in the nanoparticle-based delivery of glycoantigens. [ABSTRACT FROM AUTHOR]

The biological progression of aging encompasses complex physiological processes. As individuals grow older, their physiological functions gradually decline, including compromised immune responses, leading to immunosenescence. Immunosenescence significantly elevates disease susceptibility and severity in older populations while concurrently compromising vaccine-induced immune responses. This comprehensive review aims to elucidate the implications of immunosenescence for vaccine-induced immunity and facilitate the development of optimized vaccination strategies for geriatric populations, with specific focus on COVID-19, influenza, pneumococcal, herpes zoster, and respiratory syncytial virus (RSV) vaccines. This review further elucidates the relationship between immunosenescence and vaccine-induced immunity. This review presents a systematic evaluation of intervention strategies designed to enhance vaccine responses in older populations, encompassing adjuvant utilization, antigen doses, vaccination frequency modification, inflammatory response modulation, and lifestyle interventions, including physical activity and nutritional modifications. These strategies are explored for their potential to improve current vaccine efficacy and inform the development of next-generation vaccines for geriatric populations. [ABSTRACT FROM AUTHOR]

Background: The evaluation of HPV vaccine effectiveness is essential for informing public health strategies, yet there remains a gap in understanding humoral immune responses generated by different HPV vaccine formulations in regional populations. This study addresses this gap by evaluating the immunogenicity of the newly developed HPV vaccine Cecolin (Wantai), alongside various imported vaccines, including bivalent, quadrivalent, and nonavalent options available in China. Methods: From March 2023 to June 2024, a total of 352 participants were enrolled, including 87 females aged 9–14 years who received two doses of the bivalent HPV vaccine (Cecolin), 215 females aged 15–45 years who were fully vaccinated with various HPV vaccines, and 50 non-recipients. Follow-up assessments were conducted at six timepoints during the administration of Cecolin. Serum was collected at enrollment and at each follow-up visit for antibody assessments using a pseudovirion-based neutralization assay (PBNA). Findings: The longitudinal follow-up of females aged 9–14 years revealed a 100% conversion rate for neutralizing antibodies against HPV types 16 and 18 after the second dose, compared to 94.3% and 97.1% conversion rates six months after the first dose. Compared to participants who received full doses of quadrivalent and nonavalent vaccines, females who received two or three doses of Cecolin exhibited higher neutralizing antibody geometric mean titers (GMTs) and non-vaccine-type (HPV31 and HPV33) antibody seroconversion rates. Interpretation: The domestically produced HPV vaccine Cecolin in China demonstrates strong immunogenicity and holds promise for the large-scale vaccination of females in developing countries to prevent cervical cancer. [ABSTRACT FROM AUTHOR]

Background/Objectives: Porcine Circovirus 2 (PCV2) infection poses significant health and economic challenges to the global swine industry. The disease in pigs leads to lymphoid depletion, resulting in immunosuppression and increased susceptibility to co-infections with other bacterial and viral pathogens. This study evaluated the efficacy of two novel recombinant Newcastle disease virus (NDV) strain R2B vectored vaccines that express the cap gene of PCV2 alone and along with the transmembrane and cytoplasmic tail (TMCT) domains of the NDV F gene. The efficacy of the vaccine candidates was studied in mouse and pig models. Methods: Six-week-old BALB/c mice were divided into five groups and immunized intramuscularly three times at 14-day intervals with various vaccine candidates, namely rNDV-R2B-PCVcap-TMCT, rNDV-R2B-PCVcap, and CircoFLEX commercial vaccine, along with controls. Following immunization and PCV2d virus challenge, multiple assays assessed the immune responses in animal trials. In the pig animal trial, pigs were divided into four groups: a control group (PBS), NDV-vectored PCVcap-TMCT group, NDV-vectored-PCVcap group, and CircoFLEX vaccine group. Pigs were immunized intramuscularly twice at 28-day intervals. Blood samples were collected at regular intervals over 70 days to evaluate the humoral and cell-mediated immune responses. Results: Both mice and pigs' trials indicated that the NDV-vectored PCV2 cap-TMCT vaccine candidate elicited superior immune responses. In mice, the rNDV-R2B-PCVcap-TMCT group showed enhanced humoral and cellular immunity, increased PCV2-specific antibody levels, higher CD4+/CD8+ ratio, elevated IFN-γ and TNF-α levels, decreased IL-10 levels, reduced viral loads, and minimal histopathological changes. In pigs, the NDV-vectored PCVcap-TMCT group demonstrated better antibody responses, cytokine profiles (IFN-γ and IL-10), and higher levels of PCV2-specific neutralizing antibodies against the PCV2a, PCV2b and PCV2d genotypes when compared to other groups. Conclusions: These findings suggest NDV-vectored PCVcap-TMCT vaccine candidate, expressing the cap gene of PCV2 along with the TMCT domain, offers a promising alternative for protecting against PCV2 infection, potentially addressing the challenges posed by emerging PCV2 strains in the swine industry. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic, caused by SARS-CoV-2, prompted global efforts to develop vaccines to control the disease. Various vaccines, including mRNA (BNT162b2, mRNA-1273), adenoviral vector (ChAdOx1, Ad26.COV2.S), and inactivated virus platforms (BBIBP-CorV, CoronaVac), elicit high-titer, protective antibodies against the virus, but long-term antibody durability and effectiveness vary. The objective of this study is to elucidate the factors that influence vaccine effectiveness (VE) and the longevity of humoral immune responses to COVID-19 vaccines through a review of the relevant literature, including clinical and real-world studies. Here, we discuss the humoral immune response to different COVID-19 vaccines and identify factors influencing VE and antibody longevity. Despite initial robust immune responses, vaccine-induced immunity wanes over time, particularly with the emergence of variants, such as Delta and Omicron, that exhibit immune escape mechanisms. Additionally, the durability of the humoral immune responses elicited by different vaccine platforms, along with the identification of essential determinants of long-term protection—like pre-existing immunity, booster doses, hybrid immunity, and demographic factors—are critical for protecting against severe COVID-19. Booster vaccinations substantially restore neutralizing antibody levels, especially against immune-evasive variants, while individuals with hybrid immunity have a more durable and potent immune response. Importantly, comorbidities such as diabetes, cardiovascular disease, chronic kidney disease, and cancer significantly reduce the magnitude and longevity of vaccine-induced protection. Immunocompromised individuals, particularly those undergoing chemotherapy and those with hematologic malignancies, have diminished humoral responses and benefit disproportionately from booster vaccinations. Age and sex also influence immune responses, with older adults experiencing accelerated antibody decline and females generally exhibiting stronger humoral responses compared to males. Understanding the variables affecting immune protection is crucial to improving vaccine strategies and predicting VE and protection against COVID-19. [ABSTRACT FROM AUTHOR]

The action of mRNA-based vaccines requires the expression of the antigen in cells targeted by lipid nanoparticle–mRNA complexes. When the vaccine antigen is not fully retained by the producer cells, its local and systemic diffusion can have consequences depending on both the levels of antigen expression and its biological activity. A peculiarity of mRNA-based COVID-19 vaccines is the extraordinarily high amounts of the Spike antigen expressed by the target cells. In addition, vaccine Spike can be shed and bind to ACE-2 cell receptors, thereby inducing responses of pathogenetic significance including the release of soluble factors which, in turn, can dysregulate key immunologic processes. Moreover, the circulatory immune responses triggered by the vaccine Spike is quite powerful, and can lead to effective anti-Spike antibody cross-binding, as well as to the emergence of both auto- and anti-idiotype antibodies. In this paper, the immunologic downsides of the strong efficiency of the translation of the mRNA associated with COVID-19 vaccines are discussed together with the arguments supporting the idea that most of them can be avoided with the advent of next-generation, mucosal COVID-19 vaccines. [ABSTRACT FROM AUTHOR]

(1) Background/Objectives: Two pneumococcal conjugate vaccines, 15-(PCV15) and 20-(PCV20) valent formulations, are routinely recommended for US children in a 3+1 schedule. The first three doses are administered during the first year of life at 2, 4, and 6 months, while a booster dose is given at 12 to 15 months. This study evaluated the health and economic effects of the PCV20 infant series within the first year of life compared to PCV15. (2) Methods: Using a decision-analytic model, we calculated the health and economic effects of introducing PCV15 or PCV20 for five subsequent birth cohorts. Epidemiological data were drawn from peer-reviewed studies and estimates for vaccine effectiveness were extrapolated from established PCV13 effectiveness and PCV7 efficacy studies. Direct medical costs related to the disease treatment were extracted from the literature and inflated to 2024 dollars. (3) Results: Over the course of five years, the implementation of PCV20 vaccination for newborns in the United States, compared to PCV15, is projected to prevent an additional 220 cases of invasive pneumococcal disease, 6542 cases of community-acquired pneumonia, and 112,095 cases of otitis media within the first year of life across five subsequent birth cohorts. This strategy could prevent 66 infant deaths linked to these illnesses and confer extra health gains, amounting to 5058 years of life and 5037 quality-adjusted life years. These prevented cases are estimated to save approximately USD 147 million over 5 years. (4) Conclusions: This study demonstrated that vaccinating with PCV20 during the first 12 months of life compared to PCV15 in the US would yield a substantially greater health and economic return due to the five additional serotypes covered by PCV20. [ABSTRACT FROM AUTHOR]

Background: Serosurveillance of epidemic cerebrospinal meningitis (ECM) in healthy individuals is crucial for assessing disease risk and evaluating the effectiveness of vaccinations. However, this practical work is rare in China. Methods: We conducted cross-section serosurveillance in Guangzhou, Zhanjiang, and Heyuan in Guangdong Province, measuring Anti-Nm IgG with serogroups A, C, Y, and W, and analyzed the trends using a generalized additive model (GAM). Results: During 2019–2022, 7752 participants were included. The overall antibody positivity rate for serogroups A, C, Y, and W were 60.75%, 15.51%, 32.83%, and 14.56%, respectively. High Anti-Nm IgG was in children aged 0–5 and 5–10 years old. Geometric mean concentrations (GMCs) of Anti-Nm IgG were higher and correlated positively with vaccine doses compared with unvaccinated individuals. The GMC showed a consistent decrease trend in the vaccinated and a U-shaped curve in populations. The declined rates of GMC were 1.59 (95% CI: 1.03, 2.14) µg/mL, 1.65 (95% CI: 1.28, 2.03), 0.62 (95% CI: 0.22, 1.03), and 0.31 (95% CI: 0.08, 0.53) µg/mL per year for serogroups A, C, Y, and W, respectively. Conclusions: There were differences in antibody positivity rate and GMC for the four serogroups of ECM in the healthy individuals of Guangdong Province, with serogroup A showing the highest, and the demographic differences highlighted the high seroprevalence of Neisseria meningitidis in younger people. The variable prevalence rates among serogroups A, C, Y, and W and the observed decline in antibody titers underscore the need for adjustments in the immunization program targeting the meningococcal vaccine. [ABSTRACT FROM AUTHOR]

Aeromonas hydrophila causes motile Aeromonas septicemia (MAS), a disease with a high mortality rate in tilapia culture. Feed-based vaccines with the incorporation of inactivated whole-cell bacteria into the feed offer promising tools to control MAS. Currently, the incorporation of genome-free bacteria as bacterial vaccine through the implementation of SimCells® technology into the feed has become a particular interest. Background/Objectives: This study investigates the efficacy of a feed-based vaccine incorporating genome-free A. hydrophila (FBV-GFAH) against MAS infection in red tilapia. Methods: The vaccine was prepared and delivered at 5% fish body weight for three consecutive days in weeks 0 (prime vaccination) and 2 (first booster vaccination), orally. Throughout a five-week experimental period, the immune-related genes (IL-1β, MHC-II, CD4, IgT, and IgM) expression in the hindgut and head kidney of the fish was determined using RT-qPCR assay. Lysozyme (serum) and overall IgM (serum, gut lavage, and skin mucus) productions were also detected. Results: Fish vaccinated with FBV-GFAH showed a significant (p ≤ 0.05) improvement in relative percent survival compared with unvaccinated fish following bacterial challenge. FBV-GFAH induced the expression of immune-related genes in the hindgut and head kidney, especially after booster vaccination. Furthermore, serum lysozyme activity and overall IgM production in serum, skin mucus, and gut lavage were also significantly (p ≤ 0.05) improved in the FBV-GFAH vaccinated fish than the unvaccinated fish. Conclusions: This study showed that FBV-GFAH is a promising feed-based vaccine technology to control MAS in cultured tilapia. [ABSTRACT FROM AUTHOR]

Background/Objectives. Tuberculosis is a deadly bacterial disease and the second most common cause of death from monoinfectious diseases worldwide. Comprehensive measures taken by health authorities in various countries in recent decades have saved tens of millions of lives, but the number of new cases of this infection has been steadily increasing in the last few years and already exceeds 10 million new cases annually. The development of new vaccines against tuberculosis is a priority area in the prevention of new cases of the disease. mRNA vaccines have already shown high efficacy against COVID-19 and other viral infections and can currently be considered a promising field of antituberculosis vaccination. In our previous study, we assessed the immunogenicity and protective activity of several types of antituberculosis mRNA vaccines with different 5′ untranslated regions, but the efficacy of these vaccines was either comparable with or lower than that of BCG. Methods. Here, we conducted a comprehensive experiment to investigate the effects of cotranscriptional capping conditions and of cap structure on the magnitude of the mRNAs' translation in HEK293T and DC2.4 cells. The most effective cap version was used to create an antituberculosis mRNA vaccine called mEpitope-ESAT6. Results and Conclusions. We compared immunogenicity and protective activity between mEpitope-ESAT6 and BCG and found that the vaccine with the new cap type is more immunogenic than BCG. Nonetheless, the increased immunogenicity did not enhance vaccine-induced protection. Thus, the incorporation of different cap analogs into mRNA allows to modulate the efficacy of mRNA vaccines. [ABSTRACT FROM AUTHOR]

New vaccination programs measure economic success through cost-effectiveness analysis (CEA) based on an outcome evaluated over a certain time frame. The reimbursement price of the newly approved vaccine is then often reliant on a simulated ideal effect projection because of limited long-term data availability. This optimal cost-effectiveness result is later rarely adjusted to the observed effect measurements, barring instances of market competition-induced price erosion through the tender process. However, comprehensive and systematic monitoring of the vaccine effect (VE) for the evaluation of the real long-term economic success of vaccination is critical. It informs expectations about vaccine performance with success timelines for the investment. Here, an example is provided by a 15-year assessment of the rotavirus vaccination program in Belgium (RotaBIS study spanning 2005 to 2019 across 11 hospitals). The vaccination program started in late 2006 and yielded sub-optimal outcomes. Long-term VE surveillance data provided insights into the infection dynamics, disease progression, and vaccine performance. The presented analysis introduces novel conceptual frameworks and methodologies about the long-term economic success of vaccination programs. The CEA evaluates the initial target vaccination population, considering vaccine effectiveness compared with a historical unvaccinated group. Cost-impact analysis (CIA) covers a longer period and considers the whole vaccinated and unvaccinated population in which the vaccine has direct and indirect effects. The economic success index ratio of CIA over CEA outcomes evaluates long-term vaccination performance. Good performance is close to the optimal result, with an index value ≤1, combined with a low CEA. This measurement is a valuable aid for new vaccine introductions. It supports the establishment of robust monitoring protocols over time. [ABSTRACT FROM AUTHOR]

Background/Objectives: Japan's COVID-19 vaccination campaign achieved high coverage by 2022, yet limited national-level data has hindered evaluations of vaccine effectiveness. This study analyzed the impact of vaccines on infection outcomes while considering socioeconomic and behavioral factors in the Japanese population. Methods: A total of 19,482 individuals aged 16–81 years, who participated in both the 2021 (baseline) and 2022 (follow-up) waves of an Internet-based survey, were analyzed. Vaccine intake during the follow-up period (0/1/2+ doses) served as the exposure, while outcomes included COVID-19 diagnosis, hospitalization, and receipt of oxygenation/ventilation. Adjusted prevalence ratios (APRs) were calculated using Poisson regression models, controlling for baseline characteristics such as vaccination status, infection history, underlying medical conditions, socioeconomic factors, and preventive behaviors. Results: Overall, 81.6% of respondents received at least 1 dose of COVID-19 vaccine during the follow-up period. Among those without COVID-19 history at baseline (N = 19,182), 10.9% were diagnosed with COVID-19 in the past year, and 6.6% in the past 2 months. Respondents who received 1 or 2+ doses had lower diagnosis rates (APR = 0.76 and 0.43, respectively). For the past 2 months, only those with 2+ doses showed a significant reduction (APR = 0.51). Among 1999 diagnosed cases, those with 1 or 2+ doses showed lower hospitalization and oxygenation/ventilation likelihoods, though these differences were not statistically significant. Conclusions: The results supported the protective effect of COVID-19 vaccines against infection. Continued research is essential to further clarify the complex influence of vaccination, individual characteristics, and preventive behaviors on COVID-19 morbidity at the population level. [ABSTRACT FROM AUTHOR]

Background: Newcastle disease virus (NDV) is a highly contagious and economically devastating pathogen affecting poultry worldwide, leading to significant losses in the poultry industry. Despite existing vaccines, outbreaks continue to occur, highlighting the need for more effective vaccination strategies. Developing a multi-epitopic peptide vaccine offers a promising approach to enhance protection against NDV. Objectives: Here, we aimed to design and evaluate a multi-epitopic vaccine against NDV using molecular dynamics (MD) simulation. Methodology: We retrieved NDV sequences for the fusion (F) protein and hemagglutinin–neuraminidase (HN) protein. Subsequently, B-cell and T-cell epitopes were predicted. The top potential epitopes were utilized to design the vaccine construct, which was subsequently docked against chicken TLR4 and MHC1 receptors to assess the immunological response. The resulting docked complex underwent a 1 microsecond (1000 ns) MD simulation. For experimental evaluation, the vaccine's efficacy was assessed in mice and chickens using a controlled study design, where animals were randomly divided into groups receiving either a local ND vaccine or the peptide vaccine or a control treatment. Results: The 40 amino acid peptide vaccine demonstrated strong binding affinity and stability within the TLR4 and MHC1 receptor–peptide complexes. The root mean square deviation of peptide vaccine and TLR4 receptor showed rapid stabilization after an initial repositioning. The root mean square fluctuation revealed relatively low fluctuations (below 3 Å) for the TLR4 receptor, while the peptide exhibited higher fluctuations. The overall binding energy of the peptide vaccine with TLR4 and MHC1 receptors amounted to −15.7 kcal·mol−1 and −36.8 kcal·mol−1, respectively. For experimental evaluations in mice and chicken, the peptide vaccine was synthesized using services of GeneScript Biotech® (Singapore) PTE Limited. Experimental evaluations showed a significant immune response in both mice and chickens, with the vaccine eliciting robust antibody production, as evidenced by increasing HI titers over time. Statistical analysis was performed using an independent t-test with Type-II error to compare the groups, calculating the p-values to determine the significance of the immune response between different groups. Conclusions: Multi-epitopic peptide vaccine has demonstrated a good immunological response in natural hosts. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to estimate the effectiveness of original and bivalent COVID-19 vaccines in reducing COVID-19-associated hospitalizations among the adult population of Turin, Italy. Methods: We conducted a retrospective, test-negative, case–control study of 5768 adults aged ≥50 years who had symptoms that were consistent with COVID-19-like illness and were admitted to the hospitals of the Turin Health Unit network from 1 January 2021 to 31 January 2023. We evaluated the effectiveness of the vaccines that at the time of the study were authorized in the European Union (original/bivalent BNT162b2; original mRNA-1273; ChAdOx1-S; Ad26.COV2.S) by comparing the odds of a positive test for SARS-CoV-2 in vaccinated patients with the odds of a positive test in unvaccinated patients. The association between vaccination status, hospitalization, ICU admission and positive SARS-CoV-2 test was estimated by building multivariate adjusted logistic regression models. Results: During the predominance of the pre-Omicron variants, the vaccine effectiveness of two and three doses received in the last 120 days against COVID-19-associated hospitalizations was 93.6% (95% CI: 90.1 to 95.9) and 97.1% (95% CI: 90.8 to 99.1), respectively. During the predominance of the Omicron variant, the vaccine effectiveness of two and three doses was 26.6% (95% CI: −0.6 to 46.5) and 75.2% (95% CI: 68.1 to 80.7), respectively, and it rose to 88% (95% CI: 78.2 to 93.3) for four or five doses of the bivalent vaccine. Conclusions: Our study confirms that the COVID-19 vaccines protect adult patients from hospitalizations, including the subgroup ≥80 years, also during the period of the Omicron variant's predominance. [ABSTRACT FROM AUTHOR]

Background: Many human activities release harmful substances, contaminating the air, water, and soil. Since exposure to environmental pollutants is currently unavoidable, it is important to verify how these compounds may influence individual immune responses to vaccines. Methods: This review was conducted in accordance with the PRISMA statement. The protocol was registered on the PROSPERO platform with the following ID: CRD42024582592. We evaluated all observational, semi-experimental, and experimental studies written in both Italian and English that reported possible effects of exposure to environmental pollutants on the production of vaccine-induced antibodies. Results: Forty-two studies were included. The effects of pollutants were examined mainly in terms of antibody production in relation to mumps, measles and rubella, diphtheria and tetanus, hepatitis A and B, Haemophilus influenzae type B, influenza, tuberculosis, pertussis, Japanese encephalitis, poliomyelitis, and COVID-19 vaccines. Perfluorinated compounds were the most studied pollutants. Conclusions: Correlations between exposure to pollutants and reductions in antibody production were found in quite all the selected studies, suggesting that pollution control policies could contribute to increase the efficacy of vaccination campaigns. However, the heterogeneity of the examined studies did not allow us to perform a meta-analysis, and the literature on each type of vaccine or pollutant is still too limited to generate robust evidence. In order to confirm the findings of the present systematic review, and in the perspective of establishing possible exposure limit values for each type of pollutant, further research in this field is required. [ABSTRACT FROM AUTHOR]

Background/Objectives: To evaluate the health benefits, costs, and cost-effectiveness of vaccination with bivalent respiratory syncytial virus stabilized prefusion F vaccine (RSVpreF) for the prevention of lower respiratory tract disease caused by respiratory syncytial virus (RSV) in Greek adults 60 years of age and older. Methods: A Markov model was adapted to simulate lifetime risk of health and economic outcomes from the public payer's perspective over a lifetime horizon. Epidemiology, vaccine effectiveness, utilities, and direct medical costs (EUR, 2024) were obtained from published studies, official sources, and local experts. Model outcomes included the number of medically attended RSV cases, stratified by care setting (i.e., hospital, emergency department [ED], outpatient visits [OV]), and attributable RSV-related deaths, costs, life years (LY), quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios (ICERs) of RSVpreF vaccination compared with no vaccination. Results: The model projected 258,170 hospitalizations, 112,248 ED encounters, 1,201,604 OV, and 25,463 deaths related to RSV in Greek older adults resulting in direct medical costs of EUR 1.6 billion over the lifetime horizon. Assuming RSV vaccination would reach the same coverage rates as pneumococcal and influenza programmes, 18,118 hospitalizations, 7874 ED encounters, 48,079 OV, and 1706 deaths could be prevented over the modelled time horizon. The health benefits associated with RSVpreF contributed to an incremental gain of 10,976 LYs and 7230 QALYs compared with no vaccination. The incremental analysis reported that vaccination with RSVpreF was estimated to be a cost-effective strategy resulting in ICERs of EUR 12,991 per LY gained, EUR 19,723 per QALY gained, and EUR 7870 per hospitalized RSV case avoided compared with no vaccination. Conclusions: Vaccination with RSVpreF was a cost-effective strategy for the prevention of RSV disease in Greek adults over 60 years of age. The introduction of RSV vaccination can improve public health by averting RSV cases and deaths and has the potential to fulfil an unmet medical need. [ABSTRACT FROM AUTHOR]

Objective: COVID-19 vaccine-neutralizing antibodies provide early data on potential vaccine effectiveness, but their usefulness depends on study reliability and reporting quality. Methods: We systematically evaluated 50 published post-vaccination neutralizing antibody studies for key parameters that determine study and data quality regarding sample size, SARS-CoV-2 infection, vaccination regimen, sample collection period, demographic characterization, clinical characterization, experimental protocol, live virus and pseudo-virus details, assay standardization, and data reporting. Each category was scored from very high to low or unclear quality, with the lowest score determining the overall study quality score. Results: None of the studies attained an overall high or very high score, 8% (n = 4) attained moderate, 42% (n = 21) low, and 50% (n = 25) unclear. The categories with the fewest studies assessed as ≥ high quality were SARS-CoV-2 infection (42%), sample size (30%), and assay standardization (14%). Overall quality was similar over time. No association between journal impact factor and quality score was found. Conclusions: We found that reporting in neutralization studies is widely incomplete, limiting their usefulness for downstream analyses. [ABSTRACT FROM AUTHOR]

Background: Influenza vaccine uptake among healthcare workers is crucial for preventing influenza infections, yet its effectiveness needs further investigation. Objectives: This prospective observational study aimed to assess the protective effect of influenza vaccination among healthcare workers in Shenzhen. Methods: We enrolled 100 participants, with 50 receiving the 2023–2024 quadrivalent influenza vaccine (QIV) and 50 serving as unvaccinated controls. Epidemiological data were collected when the participants presented influenza-like illness. Serum samples were collected at three time points (pre-vaccination and 28 and 180 days after vaccination). Hemagglutination inhibition (HI) assay was performed against the strains included in the 2023–2024 QIV (H1N1, H3N2, BV and BY strains) to assess antibody protection levels. Demographics comparisons revealed no significant differences between the vaccinated and control groups (p > 0.05), ensuring group comparability. Results: The incidence of influenza-like illness was significantly lower in the vaccinated (18%) compared to the control group (36%; p = 0.046; OR = 0.39; 95% CI: 0.15 to 0.98). The vaccinated group also exhibited a higher rate of consecutive two-year vaccinations (48% vs. 24% in the control group, p < 0.05). Additionally, the vaccinated healthcare workers were more inclined to recommend vaccination to their families (80% vs. 48%, p < 0.05). HI titers against H1N1 (p < 0.01), H3N2 (p < 0.01), BV (p < 0.001) and BY (p < 0.01) significantly increased in the vaccinated group at 28 days post-vaccination. Moreover, a marked and sustained increase in HI titers against the H3N2 strain (p < 0.001) was observed at 180 days post-vaccination, highlighting the vaccine's enduring impact on the immune response. The fold change in the HI titers, indicative of the magnitude of the immune response, was significantly higher for H1N1 (p < 0.01), H3N2 (p < 0.001), BV (p < 0.01) and BY (p < 0.05) among the vaccinated individuals compared to the control group, underscoring the vaccine's efficacy in eliciting a robust and sustained antibody response. Conclusion: Influenza vaccination significantly reduces the incidence of influenza-like illness among healthcare workers and promotes a sustained immune response. The study supports the importance of annual vaccination for this group to enhance personal and public health. [ABSTRACT FROM AUTHOR]

The editorial "Vaccination and Global Health" compiles 11 papers exploring various aspects of vaccination, public health, and global healthcare systems. The articles cover topics such as vaccine development, public health implications of vaccination programs, barriers to vaccine access, and COVID-19 vaccination programs in low- and middle-income countries. The Special Issue addresses knowledge gaps in equitable vaccine access, long-term vaccine efficacy, and future research directions for improving global vaccine distribution and uptake. The authors emphasize the importance of evidence-based solutions to enhance vaccine acceptance globally through targeted educational campaigns and community engagement strategies. [Extracted from the article]

Background. The combined or multivalent vaccines are actively used in pediatric practice and offer a series of advantages, including a reduced number of injections and visits to the doctor, simplicity of the vaccination schedule and minimization of side effects, easier vaccine monitoring and storage, and lower vaccination costs. The practice of widespread use of the combined vaccines has shown the potential to increase vaccination coverage against single infections. The mRNA platform has been shown to be effective against the COVID-19 pandemic and enables the development of combined vaccines. There are currently no mRNA-based combined vaccines approved for use in humans. Some studies have shown that different mRNA components in a vaccine can interact to increase or decrease the immunogenicity and efficacy of the combined vaccine. Objectives. In the present study, we investigated the possibility of combining the mRNA vaccines, encoding seasonal influenza and SARS-CoV-2 antigens. In our previous works, both vaccine candidates have shown excellent immunogenicity and efficacy profiles in mice. Methods. The mRNA-LNPs were prepared by microfluidic mixing, immunogenicity in mice was assessed by hemagglutination inhibition assay, enzyme-linked immunoassay and virus neutralization assay. Immunological efficacy was assessed in a mouse viral challenge model. Results. In this work, we demonstrated that the individual mRNA components of the combined vaccine did not affect the immunogenicity level of each other. The combined vaccine demonstrated excellent protective efficacy, providing a 100% survival rate when mice were infected with the H1N1 influenza virus and reducing the viral load in the lungs. Four days after the challenge with SARS-CoV-2 EG.5.1.1., no viable virus and low levels of detectable viral RNA were observed in the lungs of vaccinated mice. Conclusions. The combination does not lead to mutual interference between the individual vaccines. We believe that such a combined mRNA-based vaccine could be a good alternative to separated human vaccinations for the prevention of COVID-19 and influenza. [ABSTRACT FROM AUTHOR]