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Background: Seasonal influenza is prevented through annual vaccination, especially in children and older adults. These vaccines are annually updated based on World Health Organization recommendations and require continuous safety monitoring., Objective: We assessed the frequency and severity of adverse events within 7 days of administering GSK's inactivated quadrivalent seasonal influenza vaccine (IIV4) in Belgium, Germany, and Spain during the 2022/2023 influenza season., Methods: In this enhanced safety surveillance study, adults who received GSK's IIV4 and parents/guardians/legally acceptable representatives of vaccinated children (aged 6 months-17 years) were invited to complete adverse drug reaction cards reporting adverse events within 7 days post-vaccination., Results: In total, 1332 participants (53.6% female) received at least one dose of GSK's IIV4, including 43 children who received two doses. Overall, 97.8% of adverse drug reaction cards were completed and returned in the study. All participants in Belgium were adults, while 54.7% and 7.4% in Spain and Germany, respectively, were pediatric participants aged 6 months-17 years. After Dose 1, across all age groups, 49.8% of participants reported at least one adverse event. The most common adverse events (cumulative frequency >5%) following Dose 1 were injection-site pain (37.6%), fatigue (15.0%), headache (13.2%), injection-site swelling (9.3%), myalgia (7.6%), and injection-site erythema (7.4%). Across all countries, adverse events were most common in adults aged 18-65 years (59.7%), followed by those aged 3-17 years (47.0%), >65 years (35.7%), and 6-35 months (23.5%). After Dose 2, 18.6% of participants reported at least one adverse event, with general disorders and administration site conditions again being the most frequent., Conclusions: Across all age and risk groups for serious disease, no serious adverse events related to GSK's IIV4 were reported within 7 days post-vaccination. This study supports and confirms the acceptable safety profile of GSK's IIV4 across all recommended age groups., Clinical Trial Registration: ClinicalTrials.gov number: not applicable., (© 2024. GSK.)

Rationale: Since the onset of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic in 2019, considerable resources have been devoted to developing vaccines to reduce related deaths and the burden of disease. Various vaccine formulations eventually became available and were approved for clinical use. In this article, we have conducted a review of polymyalgia rheumatica (PMR) cases induced by different COVID-19 vaccines [Pfizer: BNT162b2, AstraZeneca: ChAdOx1-S, Moderna: mRNA-1273, and Janssen: Ad26.COV2.S)], as well as non-COVID-19 vaccines, such as influenza, zoster, hepatitis B, and tetanus vaccines. Additionally, this article investigates 3 cases with clinical presentations suggestive of PMR following COVID-19 mRNA vaccination. This study aims to offer valuable insights through sharing diagnostic and therapeutic experiences., Patient Concerns: Three patients presented with severe pain and stiffness in both shoulder and pelvic girdle muscles, following COVID-19 mRNA vaccination., Diagnoses: Clinical presentations, laboratory parameters, and echographic findings confirmed the diagnosis of PMR following COVID-19 mRNA vaccination., Interventions: Patients received Prednisone and/or Methotrexate adjusted to body weight., Outcomes: Polymyalgia rheumatica resolved successfully without any adverse events., Lessons: Although direct causality was not definitively established in this article, the BNT162b2 COVID-19 mRNA vaccine, similar to other vaccines, might be considered a potential trigger for PMR. This raises the need for further research into this issue and potentially other immunological outcomes., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Vasovagal syncope, or fainting, can be triggered by various stimuli, including medical procedures. Syncope after vaccination has been reported, most commonly among adolescents, and can result in injuries. Using the Vaccine Adverse Event Reporting System (VAERS), we reviewed and summarized reports of syncope after live attenuated influenza vaccine, intranasal (LAIV) administered as the sole vaccine (i.e., no concomitant injections). From June 17, 2003 (date of LAIV licensure in the US) through May 31, 2024, VAERS received 50 reports of syncope after LAIV. Nearly half (23; 46 %) pertained to individuals 10-19 years of age. While the vast majority of reports (35; 70 %) did not describe any injuries, 15 people (30 %) were injured, most commonly by falling and hitting their head or face. Twenty-two people (44 %) required evaluation in the emergency department or doctor's office, including an individual who lost consciousness while he was driving home from the vaccination appointment. He did not report any injuries, but the car was severely damaged. Nearly three-quarters of people (37; 74 %) developed syncope within 15 min after vaccination, but fewer than half of reports (24; 48 %) stated that the patient had waited in the observation area for at 15 min. Based on approximately 111.9 million doses of LAIV distributed in the US during the same time period, the reporting rate is approximately 0.4 per million doses, suggesting that syncope following LAIV is rare. The information summarized here may enable clinicians, patients, and caregivers to make a more informed decision regarding preventing injuries that may occur following LAIV-related syncope., 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.)

Background: Reactivation of the latent varicella-zoster virus can cause herpes zoster (HZ) infection, and renal transplant recipients undergoing immunosuppressive therapy are particularly susceptible to this condition. This study aims to evaluate the potential increase in HZ incidence following influenza vaccination among this specific patient population., Methods: This study was a population-based, retrospective, self-controlled case series. Data were retrieved from Taiwan's National Health Insurance Research Database spanning the years 2008 to 2017. Patients diagnosed with HZ within a 6-month period before and after receiving the influenza vaccine were eligible for inclusion. Two distinct time intervals were defined for analysis: the initial 15 days and 30 days following vaccination were categorized as risk intervals, while all other periods served as control intervals. Incidence rate ratios (IRRs) were computed to compare HZ incidence during the risk intervals with that during the control intervals., Results: This study encompassed a cohort of 4,222 renal transplant recipients who had received the influenza vaccine. Among this group, 67 recipients were subsequently diagnosed with HZ. The IRR during both the initial 15 days (IRR = 0.63; 95 % CI, 0.23-1.89) and the first 30 days (IRR = 1.50; 95 % CI, 0.71-3.16) following influenza vaccination did not demonstrate a statistically significant increase when compared to the post-exposure observation times. Comparable results were also observed when comparing these IRR values to the pre-exposure observation times. The subgroup analysis, stratified by age, sex, and underlying medical conditions (including cancer and autoimmune diseases), revealed that the IRRs did not exhibit statistically significant differences., Conclusions: No significant association between the influenza vaccine and an elevated risk of HZ was detected. The administration of annual influenza vaccines appears to be a reasonable practice for renal transplant recipients., 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: Influenza A results in significant morbidity and mortality. VIR-2482, an engineered human monoclonal antibody with extended half-life, targets a highly conserved epitope on the stem region of influenza A hemagglutinin and may protect against seasonal and pandemic influenza., Methods: This double-blind, randomized, placebo-controlled, phase 2 study examined the safety and efficacy of VIR-2482 for seasonal influenza A illness prevention in unvaccinated healthy adults. Participants (N = 2977) were randomized 1:1:1 to receive VIR-2482 450 mg, VIR-2482 1200 mg, or placebo via intramuscular injection. Primary and secondary efficacy endpoints were the proportions of participants with reverse transcriptase-polymerase chain reaction-confirmed influenza A infection and either protocol-defined influenza-like illness (ILI) and Centers for Disease Control and Prevention-defined ILI or World Health Organization-defined ILI, respectively., Results: VIR-2482 450 mg and 1200 mg prophylaxis did not reduce the risk of protocol-defined ILI with reverse transcriptase-polymerase chain reaction-confirmed influenza A versus placebo (relative risk reduction, 3.8% [95% confidence interval (CI), -67.3 to 44.6] and 15.9% [95% CI, -49.3 to 52.3], respectively). At the 1200-mg dose, the relative risk reductions in influenza A illness were 57.2% (95% CI: -2.5 to 82.2) using Centers for Disease Control and Prevention ILI and 44.1% (95% CI: -50.5 to 79.3) using World Health Organization ILI definitions, respectively. Serum VIR-2482 levels were similar regardless of influenza status; variants with reduced VIR-2482 susceptibility were not detected. Local injection site reactions were mild and similar across groups., Conclusions: VIR-2482 1200 mg intramuscular was well tolerated but did not significantly prevent protocol-defined ILI. Secondary endpoint analyses suggest this dose may have reduced influenza A illness. Trial registration: ClinicalTrials.gov identifier, NCT05567783., Competing Interests: Potential conflicts of interest. S. K. T., D. C., D. P., M. L. A., K. B., W. W. Y., and P. S. P. are employees of Vir Biotechnology, Inc and report stock ownership in Vir Biotechnology, Inc. C. M. H. is a former employee and shareholder of Vir Biotechnology, Inc. and is a coauthor on select Vir Biotechnology, Inc. patents. J. M. and M. D. have nothing to disclose. C. F. reports receiving grant support from Vir Biotechnology, Inc. for conduct of the clinical trial. F. G. H. has received consulting fees from The University of Alabama and Krog Associates; served as a nonpaid consultant to Vir Biotechnology, Inc. and other companies involved in developing influenza therapeutics or vaccines, including Appili, Arcturus, Eradivir, Gilead, GSK, Janssen/JNJ, Fujifilm, Merck, Ridgeback, Roche/Genentech, Sanofi Pasteur, and Via Nova; is a trustee of the International Society for Influenza and other Respiratory Viruses; and has participated on a data safety monitoring board or advisory board for Imperial College London, University of Oxford, and Enanta. Cidara, Enanta, Shionogi, and Versatope have made charitable donations for Dr. Hayden's consulting time, and both Shionogi and Roche have provided meeting travel support. 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: We evaluated co-administration of adjuvanted seasonal quadrivalent influenza vaccine (FLU-aQIV) and respiratory syncytial virus (RSV) prefusion F protein-based vaccine (RSVPreF3 OA) in ≥65-year-olds., Methods: This phase 3, open-label trial randomized ≥65-year-olds to receive FLU-aQIV and RSVPreF3 OA concomitantly (Co-Ad) or sequentially, 1 month apart (Control). Primary objectives were to demonstrate the non-inferiority of FLU-aQIV and RSVPreF3 OA co-administration versus sequential administration in terms of hemagglutination inhibition (HI) titers for each FLU-aQIV strain and RSV-A and RSV-B neutralization titers, 1 month post-vaccination. Reactogenicity and safety were also assessed., Results: Overall, 1045 participants were vaccinated (Co-Ad: 523; Control: 522). Non-inferiority of FLU-aQIV and RSVPreF3 OA co-administration versus sequential administration was demonstrated in terms of HI titers for the A/Victoria(H1N1), B/Victoria, and B/Yamagata influenza strains and RSV-A neutralization titers (upper limits [ULs] of 95% confidence intervals [CIs] for adjusted geometric mean titer [GMT] ratios [Control/Co-Ad] ≤1.50) but not for A/Darwin(H3N2) HI titers (95% CI UL = 1.53). The immune response to A/Darwin(H3N2) was further assessed post-hoc using a microneutralization assay; the post-vaccination adjusted GMT ratio (Control/Co-Ad) was 1.23 (95% CI: 1.06-1.42, ie, UL ≤1.50), suggesting an adequate immune response to A/Darwin(H3N2) following co-administration. RSV-B neutralization titers were comparable between groups (95% CI UL for adjusted GMT ratio ≤1.50). Solicited adverse events were mostly mild or moderate and transient; unsolicited and serious adverse event rates were balanced between groups., Conclusions: Adjuvanted FLU-aQIV and RSVPreF3 OA had acceptable reactogenicity/safety profiles when co-administered in ≥65-year-olds, without clinically relevant interference with the immune responses to either vaccine., Clinical Trials Registration: NCT05568797., Competing Interests: Potential conflicts of interest. R. C. runs RSV studies at her trial site with Moderna and GSK and received NIHR funding to attend the World Vaccine Congress (October 2022) as part of the UK delegation; she is the Deputy Specialty Lead and the Clinical Lead for vaccine research at the North West Coast Clinical Research Network. P. L. received consulting fees from GSK and Pfizer, declares payments or honoraria from Janssen, GSK, Moderna, AstraZeneca, Pfizer, and Sanofi, and financial support for attending meetings and/or travel from AstraZeneca, Pfizer, and Sanofi. J.-F. N., M. R., and I. S.-M. report grants and funding from GSK to their institutions for conducting this clinical trial. N. D., S. G., M.-P. D., A. J., H. A. H., S. K., and N. M. are or were employed by GSK at the time the study was designed, initiated, and/or conducted. N. D., M.-P. D., H. A. H., S. K., and N. M. have stock options or shares from GSK. N. D. also reports stocks from Haleon and patents on vaccination against RSV (numbers 2218080.6 and 2303002.6). M.-P. D. is a co-applicant on a pending patent filed by GSK. S. N. M. declares being a Principal Investigator on the current trial. S. D., J. L., H. M. M., M. P. V., and M. H. R. -R. have no conflicts of interest to declare. The authors declare no other financial or non-financial relationships. 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.)

Although vaccination is considered the most effective weapon against influenza, coverage rates, national vaccination policies, and funding vary largely around the globe. Despite their huge potential for achieving herd immunity, child-focused national vaccination strategies that favor pain-free nasal vaccines are uncommon. CENTRAL, Embase, and MEDLINE were last searched on November 13, 2023. Active-controlled randomized controlled trials comparing the live-attenuated intranasal vaccine with the inactivated intramuscular influenza vaccine in children were included. Event rates of laboratory-confirmed influenza virus infection, all-cause mortality, hospitalization, serious adverse events, adverse events, and financial outcomes were extracted based on the PRISMA 2020 Guideline. PROSPERO: CRD42021285412. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using the random-effects model when at least three comparable outcomes were available. We found no significant difference between quadrivalent live-attenuated intranasal and trivalent inactivated intramuscular (OR = 1.48; 95% CI 0.49-4.45) or between trivalent live-attenuated intranasal and inactivated intramuscular vaccines (OR = 0.77, CI = 0.44-1.34) regarding their efficacy. However, the subgroup analysis of large, multi-center trials indicated that the trivalent live attenuated intranasal influenza vaccine was superior to the trivalent inactivated intramuscular influenza vaccine (12,154 people, OR = 0.50, CI = 0.28-0.88). Only 23 "vaccine-related serious adverse events" were recorded among 17 833 individuals, with no significant difference between methods. The widespread initiation of pediatric national flu vaccination programs prioritizing the live-attenuated intranasal influenza vaccine would be beneficial. Multi-continent, high-quality studies that include children younger than two years old and those living in subtropical and tropical regions are needed to further enhance our understanding., (© 2024. The Author(s).)

Importance: Quadrivalent adjuvanted inactivated influenza vaccine (aIIV4) and adjuvanted recombinant zoster vaccine (RZV) contain novel adjuvants. Data are limited on the comparative safety, reactogenicity, and health-related quality of life (HRQOL) effects of the simultaneous administration of these vaccines., Objective: To compare the safety and reactogenicity after simultaneous doses of RZV and aIIV4 administration (opposite arms) with simultaneous doses of RZV with quadrivalent high-dose inactivated influenza vaccine [HD-IIV4])., Design, Setting, and Participants: This randomized blinded clinical trial was conducted during the 2021-2022 and 2022-2023 influenza seasons at 2 centers in the US among community-dwelling adults aged 65 years or older. Analysis was performed on an intention-to-treat basis., Intervention: Simultaneous intramuscular administration of RZV dose 1 and aIIV4 or HD-IIV4 in opposite arms after age stratification (65-69 and ≥70 years) and randomization., Main Outcomes and Measures: The primary outcome was the proportions of participants with 1 or more severe solicited reactions during days 1 to 8, using a noninferiority test (10% noninferiority margin). Additional measures included serious adverse events and adverse events of clinical interest during days 1 to 43 of the study period., Results: A total of 267 adults (median age, 71 years [range, 65-92 years]; 137 men [51.3%]) were randomized; 130 received simultaneous RZV and aIIV4, and 137 received simultaneous RZV and HD-IIV4. The proportion of patients reporting 1 or more severe reactions after simultaneous administration of RZV and aIIV4 (15 of 115 [11.5%]) was noninferior compared with simultaneous RZV and HD-IIV4 (17 of 119 [12.5%]) (absolute difference, -1.0% [95% CI, -8.9% to 7.1%]). There were no significant differences in the number of serious adverse events or adverse events of clinical interest between the groups., Conclusions and Relevance: In this clinical trial of simultaneous doses of RZV and aIIV4 compared with simultaneous doses of RZV and HD-IIV4, overall safety findings were similar between groups. From a safety standpoint, this study supports the simultaneous administration of RZV and aIIV4 among older adults., Trial Registration: ClinicalTrials.gov Identifier: NCT05007041.

Background: Older adults (aged ≥65 years) show increased susceptibility to severe disease with influenza virus infection, accounting for 70-85% of annual influenza-related fatalities in the USA. Stimulating mucosal antibodies and T cells might enhance the low vaccine effectiveness seen in older adults for currently licensed inactivated influenza vaccines, which induce mainly serum antibodies. We aimed to evaluate the safety and immunogenicity of the intranasal H3N2 M2-deficient single-replication (M2SR) vaccine, alone or coadministered with a licensed inactivated influenza vaccine (Fluzone High-Dose Quadrivalent; hereafter referred to as Fluzone HD), in older adults., Methods: In this multicentre, randomised, double-blind, double-dummy, phase 1b trial, individuals aged 65-85 years who were considered healthy or with stable chronic conditions with no recent (<6 months) influenza vaccinations were recruited from five clinical trial sites in the USA and randomly assigned (3:3:3:1) using a permuted block design to receive the H3N2 M2SR vaccine and Fluzone HD, the H3N2 M2SR vaccine and placebo, Fluzone HD and placebo, or placebo alone. All participants received a single intranasal spray and a single intramuscular injection, whether active or placebo, to maintain masking. The primary outcome was to assess the safety of H3N2 M2SR, administered alone or with Fluzone HD, in the safety analysis set, which included all participants who were randomly assigned and received treatment. Serum and mucosal antibodies were assessed as a secondary endpoint, and cell-mediated immunity as an exploratory endpoint, in participants in the per-protocol population, which included individuals in the safety analysis set without major protocol deviations. This trial is registered with ClinicalTrials.gov, NCT05163847., Findings: Between June 14 and Sept 15, 2022, 305 participants were enrolled and randomly assigned to receive the H3N2 M2SR vaccine plus placebo (n=89), H3N2 M2SR vaccine plus Fluzone HD (n=94), Fluzone HD plus placebo (n=92), or placebo alone (n=30). All randomly assigned participants were included in the safety analysis set. The most frequently reported local symptoms up to day 8 in groups that received M2SR were rhinorrhoea (43% [38 of 89] in the H3N2 M2SR plus placebo group and 38% [36 of 94] in the H3N2 M2SR plus Fluzone HD group), nasal congestion (51% [45 of 89] and 35% [33 of 94]), and injection-site pain (8% [seven of 89] and 49% [46 of 94]), and the most frequently reported solicited systemic symptoms were sore throat (28% [25 of 89]) for M2SR and decreased activity (26% [24 of 94]) for the M2SR plus Fluzone HD group. In the Fluzone HD plus placebo group, the most frequently reported local symptom was injection-site pain (48% [44 of 92]) and systemic symptom was muscle aches (22% [20 of 92]). The frequency of participants with any treatment-emergent adverse event related to vaccination was low across all groups (2-5%). One serious adverse event was reported, in a participant in the Fluzone HD plus placebo group. M2SR with Fluzone HD induced seroconversion (≥four-fold increase in haemagglutination inhibition antibodies from baseline to day 29) in 44 (48%) of 91 participants, compared with 28 (31%) of 90 participants who seroconverted in the Fluzone HD plus placebo group (p=0·023). M2SR with Fluzone HD also induced mucosal and cellular immune responses., Interpretation: The H3N2 M2SR vaccine coadministered with Fluzone HD in older adults was well tolerated and provided enhanced immunogenicity compared with Fluzone HD administered alone, suggesting potential for improved efficacy of influenza vaccination in this age group. Additional studies are planned to assess efficacy., Funding: US Department of Defense., Competing Interests: Declaration of interests JE is a consultant for FluGen. RB, HG, and KC serve on a clinical advisory board for FluGen. YK and GN are founders of FluGen. RH, DM, MJM, and PB are employees of FluGen. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Mixed cryoglobulinemia is a small vessel vasculitis associated with viral infections, mainly hepatitis C virus, however, other important causes include lymphoproliferative and autoimmune disorders. Influenza vaccine-induced cryoglobulinemia has been rarely reported. A 68-year-old male presented on three occasions following influenza vaccination with purpuric rash and lower extremities swelling. His lab work showed mixed cryoglobulins. On his most recent presentation, in addition to the purpura, he presented with thrombocytopenia and nephritic syndrome. A kidney biopsy showed endocapillary proliferative glomerulonephritis with organized deposits, consistent with mixed type cryoglobulinemic glomerulonephritis. The patient was treated with rituximab infusion with progressive improvement of the acute kidney injury (AKI) and complete recovery. It is unclear why cryoglobulins are produced as a response to a vaccination, but this association is important to be aware of for prompt monitoring and treatment.

Background: To clarify the risk of adverse ocular events following influenza vaccination., Methods: This self-controlled case series study used a claims database linked to vaccination records of a large city in Japan between April 2014 and September 2021. Individuals aged ≥ 65 years who developed adverse ocular events during the follow-up period were included. The exposure was influenza vaccination. The primary outcome was defined as the occurrence of at least one of the following five eye diseases: uveitis, scleritis, retinal vein occlusion, retinal artery occlusion, or optic neuritis. Conditional Poisson regression was used to estimate the within-subject incidence rate ratio of ocular adverse events during the risk period (0-56 days after vaccination) compared to the control period., Results: A total of 4,527 cases were eligible for the study (median age, 74 years; male, 42%). The incidence rate ratio for the outcome during the risk period was 0.99 (95% confidence interval, 0.87 to 1.14). No increased risk was observed for individual components of the outcome either; the incidence rate ratio was 0.94 (0.78 to 1.13) for uveitis, 1.17 (0.86 to 1.59) for scleritis, 0.98 (0.76 to 1.27) for retinal vein occlusion, 0.89 (0.42 to 1.87) for retinal artery occlusion, and 0.87 (0.44 to 1.70) for optic neuritis., Conclusions: This self-controlled case series showed no apparent increase in the risk of adverse ocular events after influenza vaccination among older adults. These results mitigate the concerns of older adults who may hesitate to receive influenza vaccination for fear of adverse ocular events., Abbreviation: HR = hazard ratio; CI = confidence interval; RVO = retinal vein occlusion; SCCS = self-controlled case series.

We report a case of Influenza type B (lineage Yamagata) infection in a child who received the live attenuated influenza virus vaccine before being diagnosed with B-cell acute lymphoblastic leukemia. The patient developed a mild disease that persisted for 18 days and resolved without antiviral treatment. The prolonged infection of an attenuated virus in an immunocompromised host might pose a risk of reversion or evolution to a more pathogenic strain. Prompt prevention, identification, and monitoring of similar cases are desirable to avoid the development of severe illness, which could complicate patient management., Competing Interests: Declarations 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: Immunogenicity of influenza and pneumococcal vaccines varies and requires further elucidation in patients with multiple sclerosis (MS) under treatment with disease-modifying therapies (DMTs)., Methods: Adult MS patients who consented with vaccination after standard-of-care consultation by their treating physicians were enrolled. All received a single dose of an inactivated quadrivalent influenza vaccine and of the 23-valent pneumococcal vaccine. A blood sample was collected before and after four weeks of vaccination for measurement of antibodies against Influenza A, B and S. pneumoniae. Patients were followed-up for adverse events and MS relapse for 12 months., Results: One hundred and seventy-two patients (65.7 % female, mean age 42 ± 13 years old, mean MS duration 7.6 ± 7.2 years, 81.4 % under DMTs) were enrolled from November 2019 to March 2020. Antibody measurements were available for 151 patients. Seropositivity for anti-PPSV23 did not differ between baseline and at 4 weeks of follow-up (n = 56, 37.1 %). There was a significant increase of absolute antibody titers post-vaccination for both influenza A and B (p < 0.001). For Influenza A, seropositivity was evident for 57 (37.7 %) patients at 4 weeks compared to 19 (12.6 %) patients at baseline (p McNemar  < 0.001). For Influenza Β, 110 (72.8 %) seroconverted 4 weeks after vaccination compared to 12 (7.9 %) at baseline (p McNemar  < 0.001). Interferon and fumarate did not affect influenza seroconversion while rituximab was associated with lower titers. Mild local AEs (pain, edema) were observed in 23.8 %; no severe AE was reported. Thirty-four patients (19.8 %) had a relapse during the 12-month follow-up; none was attributed to the vaccination., Conclusions: Seroconversion in MS patients on treatment was more frequent following influenza compared to PPSV23 vaccination. Rituximab had an effect on the height of the immune response. Better immunization coverage as well as future evaluation of the breadth of immune response elicited by immunization is necessary for these patients., 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: Intranasal administration of respiratory vaccines offers many advantages such as eliciting both systemic and mucosal immunity at the point of viral entry. Immunogenicity of intranasal vaccination can be improved through the use of adjuvants. Bacteria-like particles derived fromLactococcus lactishave the potential to serve as a vaccine adjuvant.This clinical study investigated the safety, reactogenicity and immunogenicity of intranasal seasonal influenza vaccine adjuvanted with gram-positive matrix particles (FluGEM®)., Methods: This was a first-in-human, randomized, double-blind, controlled, dose-escalation study performed at the Centre for Human Drug Research (CHDR), the Netherlands. Participants aged 18-49 were randomized in a 3:1 ratio to receive FluGem® in ascending doses (two-dose regimens) together with a standard trivalent inactivated influenza vaccine or unadjuvanted TIV only. Primary outcomes were safety and tolerability. Secondary outcomes were serum hemagglutination inhibition (HI) antibody titers and mucosal IgA. The most immunogenic dose was used in an additionalelderly cohort (>65 years)., Results: Ninty participants were included. Intranasal FluGem®was safe and well tolerated. The majority of adverse events were mild (97.4 %) with (un)solicited adverse events comparable across all dose levels and control groups. All groups showed geometric mean increases ≥ 2.5-fold. Seroconversion (≥40 % participants) was achieved at both day 21 (single-dose) and 42 (two-dose) for the 1.25 mg dose and on day 42 (two-dose only) for the 2.5 mg dose. Highest geometric mean IgA increases were observed in the 1.25 mg group on day 21. Immunogenicity was less pronounced in elderly., Conclusions: Intranasal vaccination of FluGEM®was safe and tolerable in healthy adult volunteers aged 18-49 years and 65 and older. Highest immunogenicity was observed for 1.25 mg and 2.5 mg doses (compared to 5 mg) suggesting a potential non-linear dose-response relationship.More research is needed to further investigate the capabilities of bacteria-like peptides as adjuvants., Competing Interests: Declaration of competing interest Kees Leenhouts and Bert-Jan Haijema were former employees of Mucosis BV. The study was sponsored by Mucosis BV. For the 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 Author(s). Published by Elsevier Ltd.. All rights reserved.)

Importance: Although influenza vaccination has been found to be safe in pregnancy, few studies have assessed repeated influenza vaccination over successive pregnancies, including 2 vaccinations in a year, in terms of adverse perinatal outcomes., Objective: To examine the association of seasonal influenza vaccination across successive pregnancies with adverse perinatal outcomes and whether the association varies by interpregnancy interval (IPI) and vaccine type (quadrivalent or trivalent)., Design, Setting, and Participants: This retrospective cohort study included individuals with at least 2 successive singleton live-birth pregnancies between January 1, 2004, and December 31, 2018. Data were collected from the Vaccine Safety Datalink, a collaboration between the Centers for Disease Control and Prevention and integrated health care organizations. Data analysis was performed between January 8, 2021, and July 17, 2024., Exposures: Influenza vaccination was identified using vaccine administration codes. The vaccinated cohort consisted of people who received influenza vaccines during the influenza season (August 1 through April 30) in 2 successive pregnancies. The comparator cohort consisted of people identified as unvaccinated during both pregnancies., Main Outcomes and Measures: Main outcomes were risk of preeclampsia or eclampsia, placental abruption, fever, preterm birth, preterm premature rupture of membranes, chorioamnionitis, and small for gestational age among individuals with and without vaccination in both pregnancies. Adjusted relative risks (RRs) from Poisson regression were used to assess the magnitude of associations. The associations with adverse outcomes by IPI and vaccine type were evaluated., Results: Of 82 055 people with 2 singleton pregnancies between 2004 and 2018, 44 879 (54.7%) had influenza vaccination in successive pregnancies. Mean (SD) age at the start of the second pregnancy was 32.2 (4.6) years for vaccinated individuals and 31.2 (5.0) years for unvaccinated individuals. Compared with individuals not vaccinated in both pregnancies, vaccination in successive pregnancies was not associated with increased risk of preeclampsia or eclampsia (adjusted RR, 1.10; 95% CI, 0.99-1.21), placental abruption (adjusted RR, 1.01; 95% CI, 0.84-1.21), fever (adjusted RR, 0.87; 95% CI, 0.47-1.59), preterm birth (adjusted RR, 0.83; 95% CI, 0.78-0.89), preterm premature rupture of membranes (RR, 1.00; 95% CI, 0.94-1.06), chorioamnionitis (adjusted RR, 1.03; 95% CI, 0.90-1.18), or small for gestational age birth (adjusted RR, 0.99; 95% CI, 0.93-1.05). IPI and vaccine type did not modify the observed associations., Conclusions and Relevance: In this large cohort study of successive pregnancies, influenza vaccination was not associated with increased risk of adverse perinatal outcomes, irrespective of IPI and vaccine type. Findings support recommendations to vaccinate pregnant people or those who might be pregnant during the influenza season.

Background: Several cases of renal complications, including acute kidney injury (AKI), after influenza vaccination have been reported, but the association remains unproven. We evaluated the association between influenza vaccination and AKI occurrence among the Korean elderly in the 2018-2019 and 2019-2020 seasons., Methods: We used a large database combining vaccination registration data from the Korea Disease Control and Prevention Agency and claims data from the National Health Insurance Service. The study subjects were patients hospitalized with AKI for the first-time following vaccination among those who received one influenza vaccine in the 2018-2019 or 2019-2020 season. Only those aged 65 or older at the date of vaccination were included. We performed a self-controlled case series study, designating the risk period as 1 to 28 days post-vaccination and the observation period as each influenza season. The adjusted incidence rate ratio (aIRR) was calculated by adjusting for nephrotoxic drug use and influenza infection that may influence AKI occurrence using a conditional Poisson regression model., Results: A total of 16 713 and 16 272 AKI events were identified during the 2018-2019 and 2019-2020 seasons, respectively. The aIRR for AKI was 0.83 (95% confidence interval [CI] = 0.79-0.87) in the 2018-2019 season. The aIRR for the 2019-2020 influenza season was similar to the 2018-2019 season (aIRR = 0.86; 95% CI = 0.82-0.90)., Conclusions: Influenza vaccination is associated with a lower risk of AKI in the elderly over 65. This evidence supports the recommendation of annual influenza vaccination for the elderly. Further studies are needed to determine the biological mechanisms linking the influenza vaccine and AKI., (© 2024 The Author(s). Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.)

Influenza affects millions of people worldwide each year and can lead to severe complications, hospitalizations, and even death, especially among vulnerable populations such as older adults and those with chronic medical conditions. Annual vaccination is considered the most effective measure for preventing influenza and its complications. Despite the widespread availability of influenza vaccines, however, vaccination coverage rates remain suboptimal in several countries. Based on the latest scientific evidence and expert opinions on influenza vaccination in older people and patients with chronic disease, the Portuguese Society of Pulmonology (SPP), the Portuguese Society of Diabetology (SPD), the Portuguese Society of Cardiology (SPC), the Portuguese Society of Geriatrics and Gerontology (SPGG), the Study Group of Geriatrics of the Portuguese Society of Internal Medicine (NEGERMI-SPMI), and the Portuguese Society of Infectious Diseases and Clinical Microbiology (SPDIMC) discussed best practices for promoting vaccination uptake and coverage and drew up several recommendations to mitigate the impact of influenza. These recommendations focus on the efficacy and safety of available vaccines; the impact of influenza vaccination on older adults; patients with chronic medical conditions, namely cardiac and respiratory conditions, diabetes, and immunosuppressive diseases; and health care professionals, optimal vaccination timing, and strategies to increase vaccination uptake and coverage. The resulting position paper highlights the critical role that vaccinations play in promoting public health, raising awareness, and encouraging more people to get vaccinated., Competing Interests: Conflicts of interest FF received personal fees and non-financial support from Sanofi, MSD, AstraZeneca and GSK. AT has no interests to declare. BA received lecture fees and honoraria from Lilly, Boehringer Ingelheim, Menarini Diagnostic, Roche Diagnostic, Sanofi and Novonordisk. JFR received personal fees from Sanofi JO received lecture and scientific consultancy fees from Gilead Sciences, Sanofi Portugal, MSD and Viiv HealthCare SD received lecture fees and honoraria from Sanofi, GSK and Pfizer. MC received personal fees from GKS, Ferrer, Sanofi and Tecnimede. AM received personal fees and non-financial support from Boheringer Ingelheim, Sanofi, MSD, AstraZeneca and Bial., (Copyright © 2023 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Influenza vaccine has rarely been associated with the occurrence of systemic inflammatory diseases., Objective: To present a case of adult-onset Still's disease (AOSD) following influenza vaccination, and subsequently explore the possible association between AOSD and influenza vaccination, as well as implications for clinical practice., Methods: Case report., Results: We report a case of 20-year-old woman who developed typical AOSD, characterized by spiking fever, arthritis and salmon-pink rash, one week after influenza vaccination. She responded well to systemic corticosteroids therapy. This is the first case report of influenza vaccination-associated AOSD from Thailand., Conclusions: Influenza vaccination may be a trigger of AOSD but more data are needed to confirm the association. History of recent vaccination should be explored in patients suspected of having systemic inflammatory diseases including AOSD.

Purpose: To determine the risk of optic neuritis (ON) after mRNA Coronavirus Disease 2019 (COVID-19) vaccine administration., Design: U.S. National aggregate database retrospective cohort study., Participants: Patients were placed into cohorts based on mRNA COVID-19 vaccination status (no vaccine and positive history of COVID-19 infection, 1 vaccine, or 2 vaccines received) from December 2020 to June 2022. Two control cohorts were created with patients vaccinated against influenza or tetanus, diphtheria, and pertussis (Tdap) from June 2018 to December 2019. Patients with any history of ON or significant risk factors for ON development including infectious, inflammatory, and neoplastic diseases were excluded., Methods: A large deidentified database was queried for the Common Procedural Technology codes for immunization encounters specific to first dose and second dose of mRNA COVID-19 vaccine, influenza, or Tdap. Cohorts were 1:1 propensity score matched on age, sex, race, and ethnicity. The risk of ON development after vaccination was calculated and compared for all 5 cohorts with 95% confidence intervals (CIs) reported., Main Outcome Measures: Risk ratio (RR) of ON 21 days after vaccination (or COVID-19 infection) and incidence of ON per 100 000 individuals., Results: After matching, the first dose COVID-19 and influenza vaccine cohorts (n = 1 678 598, mean age [standard deviation] at vaccination of 45.5 [23.3] years and 43.2 [25.5] years, 55% female) the RR of developing ON was 0.44 (95% CI, 0.28-0.80). The first dose of COVID-19 and Tdap vaccinations (n = 797 538, mean age 38.9 [20.0] years, 54.2% female) cohort had 10 and 16 patients develop ON (RR, 0.63; 95% CI, 0.28-1.38). Comparison of COVID-19-vaccinated patients (n = 3 698 848, 48.2 [21.5] years, 54.7% female) to unvaccinated and COVID-19-infected patients (n = 3 698 848, 49.6 [22.0] years, 55.2% female) showed 49 and 506 patients developing ON, respectively (RR, 0.09; 95% CI, 0.07-0.12). The incidence per 100 000 for ON was 1 in the first dose COVID-19 vaccine cohort, 2 in the influenza cohort, and 2 in the Tdap cohort, and 14 in the COVID-19-infected and unvaccinated cohorts., Conclusions: Risk of ON after mRNA COVID-19 vaccination is rare and comparable to Tdap vaccination, decreased compared with influenza vaccination, and decreased compared with COVID-19 infection in the absence of vaccination., Financial Disclosure(s): Proprietary or commercial disclosure may be found after the references., (Copyright © 2024 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Influenza is highly prevalent in children under five years, particularly those under two, accounting for 5-10% of acute respiratory infections (ARIs) in India. This study was conducted to compare the immunogenicity and safety of two tetravalent inactivated influenza vaccines in healthy children aged 6-35 months. The dose recommendation for this group increased from 0.25 mL to 0.5 mL to ensure adequate immune response, as per the Advisory Committee on Immunization Practices. This Phase III, randomized, single-blind, active-controlled, multicentre study was conducted from May to October 2022 across five centers in India. A total of 346 subjects were randomized to receive two doses of either the test vaccine (Vaxiflu-4, Zydus Lifesciences Limited; n  = 174) or the reference vaccine (Fluarix Tetra, GlaxoSmithKline; n  = 172). The primary objective was to compare immunogenicity using seroprotection rate, seroconversion rate, and geometric mean titers (GMTs) against four vaccine strains. Safety profiles were also compared. Both vaccines demonstrated non-inferiority, with seroprotection rates over 95%, seroconversion rates above 90%, and significant GMT increases. Adverse events (AEs) were similar for both vaccines, including pain at the injection site, erythema, swelling, and pyrexia. The test vaccine, Vaxiflu-4, showed non-inferiority in terms of immunogenicity and safety when compared with reference vaccine, Fluarix Tetra (Clinical trial registry number: CTRI/2022/05/042514).

The immunogenicity and safety of the concomitant administration of recombinant COVID-19 vaccine and quadrivalent inactivated influenza vaccine (Split Virion) (QIIV) in Chinese adults are unclear. In this open-label, randomized controlled trial, participants aged ≥ 18 years were recruited. Eligible healthy adults were randomly assigned (1:1) to receive QIIV at the same time as the first dose of COVID-19 vaccine (simultaneous-group) or 14 days after the second dose of COVID-19 vaccine (non-simultaneous-group). The primary outcome was to compare the difference in immunogenicity of QIIV (H1N1, H3N2, Yamagata, and Victoria) between the two groups. A total of 299 participants were enrolled, 149 in the simultaneous-group and 150 in the non-simultaneous-group. There were no significant differences in geometric mean titer (GMT) [H1N1: 386.4 (95%CI: 299.2-499.0) vs. 497.4 (95%CI: 377.5-655.3); H3N2: 66.9 (95%CI: 56.1-79.8) vs. 81.4 (95%CI: 67.9-97.5); Yamagata: 95.6 (95%CI: 79.0-115.8) vs. 74.3 (95%CI: 58.6-94.0); and Victoria: 48.5 (95%CI: 37.6-62.6) vs. 65.8 (95%CI: 49.0-88.4)] and seroconversion rate (H1N1: 87.5% vs. 90.1%; H3N2: 58.1% vs. 62.0%; Yamagata: 75.0% vs. 64.5%; and Victoria: 55.1% vs. 62.8%) of QIIV antibodies between the simultaneous and non-simultaneous groups. For the seroprotection rate of QIIV antibodies, a higher seroprotection rate of Yamagata antibody was observed only in the simultaneous-group than in the non-simultaneous-group [86.0% vs. 76.0%, p  = .040]. In addition, no significant difference in adverse events was observed between the two groups (14.2% vs. 23.5%, p  = .053). In conclusion, no immune interference or safety concerns were found for concomitant administration of COVID-19 vaccine with QIIV in adults aged ≥ 18 years.

Enhanced Passive Safety Surveillance (EPSS) was conducted for quadrivalent inactivated split-virion influenza vaccines (IIV4) in Germany (high dose [HD]) and Finland (standard dose [SD]) for the northern hemisphere (NH) 2022/23 influenza season. The primary objective was to assess adverse events following immunization (AEFI) occurring ≤7 days post-vaccination. In each country, the EPSS was conducted at the beginning of the NH influenza season. Exposure information was documented using vaccination cards (VC), and AEFI were reported via an electronic data collection system or telephone. AEFI were assessed by seriousness and age group (Finland only). The vaccinee reporting rate (RR) was calculated as the number of vaccinees reporting ≥ 1 AEFI divided by the total vaccinees. In Germany, among 1041 vaccinees, there were 31 AEFI (ten vaccinees) during follow-up, including one serious AEFI. Of 16 AEFI (six vaccinees) with reported time of onset, 15 occurred ≤7 days post-vaccination (RR 0.58%, 95% confidence interval [CI] 0.21, 1.25), which was lower than the 2021/22 season (RR 1.88%, 95% CI: 1.10, 3.00). In Finland, among 1001 vaccinees, there were 142 AEFI (51 vaccinees) during follow-up, none of which were serious. Of 133 AEFI (48 vaccinees) with time of onset reported, all occurred ≤7 days post-vaccination (RR 4.80%, 95% CI: 3.56, 6.31), which was similar to the 2021/22 season (RR 4.90%, 95% CI: 3.65, 6.43). The EPSS for HD-IIV4 and for SD-IIV4 in the 2022/23 influenza season did not suggest any clinically relevant changes in safety beyond what is known/expected for IIV4s.

Background: Systemic lupus erythematosus (SLE), an extensive autoimmune disorder, compromises viral resistance and alters immune responses post respiratory virus vaccines. This study aims to assess immune response levels and safety in SLE patients following respiratory virus vaccines., Methods: Extensive searches, until 1 March 2024, were conducted using PubMed, EMBASE, and Cochrane Library. Outcomes, encompassing seroconversion rate (SCR), antibody and IgG titers, neutralizing antibodies, anti-spike antibodies, anti-receptor binding domain (RBD) IgG, and adverse events, were appraised., Results: Sixteen articles, comprising 25 observational studies, were included. SLE patients exhibited lower SCR (OR = 0.42, 95%CI: 0.26 to 0.69), antibody titers (SMD=-2.84, 95%CI: -3.36 to -1.61), and neutralizing antibodies (OR = 0.27, 95%CI: 0.13 to 0.56) compared to the healthy population post respiratory virus vaccines. Notably, differences were statistically insignificant for anti-RBD IgG (OR = 1.75, 95%CI: 0.10 to 29.42), IgG titers (SMD=-2.54, 95%CI: -5.57 to -0.49), anti-spike antibodies (OR = 0.35, 95%CI: 0.08 to 1.53), injection site discomfort (OR = 1.03, 95%CI: 0.52 to 2.06), fatigue (OR = 1.23, 95%CI: 0.74 to 2.03), fever (OR = 1.02, 95%CI: 0.64 to 1.63), localized reactions (OR = 0.69, 95%CI: 0.37 to 1.30), systemic reactions (OR = 1.00, 95%CI: 0.59 to 1.69), allergic reactions (OR = 5.11, 95%CI: 0.24 to 107.10), self-reported vaccination-related adverse events (OR = 1.61, 95%CI: 0.56 to 4.63), and disease flares after vaccination (OR = 1.00, 95%CI: 0.14 to 7.28)., Conclusion: Despite the reduced immune response and host protection in SLE patients post-Corona Virus Disease 2019 (COVID-19) and influenza vaccines compared to the healthy population, safety profiles are comparable. Therefore, it is recommended that SLE patients receive COVID-19 and influenza viral vaccines to fortify their resistance.

Objectives: This study was to assess the lot-to-lot consistency, immunogenicity and safety of three manufacturing lots of a quadrivalent inactivated influenza vaccine (IIV4)., Methods: A randomized, double-blind, phase IV clinical trial was conducted in healthy children, adolescents and adults aged 9-59 years in Guizhou Province, China. Eligible participants were enrolled and randomized into three groups in a ratio of 1:1:1 to receive a single dose of one of three manufacturing lots of IIV4. Serum samples were collected before and 28 days after vaccination for hemagglutination inhibition (HI) antibody testing. Safety data were collected for up to 28 days after vaccination. The primary objective was to evaluate the lot-to-lot consistency of immune response as assessed by the geometric mean titer (GMT) of HI antibody at 28 days after vaccination., Results: Between November 27, 2022 and December 18, 2022, 1260 eligible participants were enrolled, with similar participant demographics among groups. Immune responses after vaccination were comparable across groups, with the 95% confidence intervals (CIs) of GMT ratios for all 4 strains falling into the equivalence criterion of (0.67, 1.5). The seroconversion rates (SCRs) and seroprotection rates (SPRs) met the US Center or Biologics Evaluation and Research (CBER) criteria for all strains for each lot (lower limit of 95% CI of SCR ≥ 40% and SPR ≥ 70%). The incidences of solicited and unsolicited adverse reactions were similar among three groups, most of which (91.9%) were mild or moderate in severity. A total of 11 serious adverse events were reported during the study, and all were considered unrelated to vaccination., Conclusion: The three manufacturing lots of IIV4 demonstrated consistent immunogenicity. IIV4 can elicit satisfactory immune responses for all four strains and no safety concerns were identified., Clinical Trial Registration: Identifier No. NCT05512494., Competing Interests: Declaration of competing interest Yuwei Li, Danyu and Jieru Wang are employed by Sinovac Biotech Co., Ltd. Xinyi Yang, and Siliang Zhou are employed by Sinovac Life Sciences Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Concomitant administration of COVID-19, influenza, and pneumococcal vaccines could reduce the burden on healthcare systems. However, the immunogenicity and safety of various combinations of a third booster dose of SARS-CoV-2 inactivated vaccine (CoronaVac), inactivated quadrivalent influenza vaccine (IIV4), and 23-valent pneumococcal polysaccharide vaccine (PPV23), particularly in different age groups, is still unknown., Methods: A phase 4, randomized, open-label, controlled trial was conducted in Beijing, China. 636 healthy adults were divided into two age groups (18-59 and ≥60 years) and randomized equally into three groups: CoronaVac and IIV4 followed by PPV23; CoronaVac and PPV23 followed by IIV4; or CoronaVac followed by IIV4 and PPV23, with a 28-day interval between vaccinations. Immunogenicity was evaluated by measuring antibody titers, and safety was monitored. ClinicalTrials.gov Identifier: NCT05298800., Results: Co-administration of a third dose of CoronaVac, IIV4, and PPV23 in any combination was safe. Among adults aged 18-59, co-administration with PPV23 maintained non-inferiority of antibody levels for CoronaVac and IIV4, despite a slight reduction in antibody responses. This reduction was not observed in participants ≥60 years. Furthermore, co-administration of IIV4 and PPV23 affected seroconversion rates for both vaccines., Conclusions: Co-administration of the third dose of SARS-CoV-2 inactivated vaccine with the influenza vaccine, followed by PPV23, may be optimal for adults aged 18-59. In adults ≥60, all vaccine combinations were immunogenic, suggesting a flexible vaccination approach. Since antibody measurements were taken 28 days post-vaccination, ongoing surveillance is essential to assess the longevity of the immune responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Bai, Zhou, Zhang, Chen, Lv, Wang, Zhang, Wu and Zhao.)

Background: Since influenza and respiratory syncytial virus (RSV) carry significant burden in older adults with overlapping seasonality, vaccines for both pathogens would ideally be coadministered in this population. Here we evaluate the immunogenicity and safety of concomitant administration of Ad26.RSV.preF/RSV preF protein and high-dose seasonal influenza vaccine (Fluzone-HD) in adults ≥65 years old., Methods: Participants were randomized 1:1 to the Coadministration or Control group. The Coadministration group received concomitant Ad26.RSV.preF/RSV preF protein and Fluzone-HD on day 1 and placebo on day 29, while the Control group received Fluzone-HD and placebo on day 1 and Ad26.RSV.preF/RSV preF protein on day 29. Influenza hemagglutination-inhibiting and RSV preF-binding antibody titers were measured postvaccination and tested for noninferiority between both groups. Safety data were collected throughout the study and analyzed descriptively., Results: Coadministered Ad26.RSV.preF/RSV preF protein and Fluzone-HD vaccines induced noninferior immune responses compared to each vaccine administered alone. Seroconversion and seroprotection rates against influenza were similar between groups. Both vaccines remained well tolerated upon concomitant administration., Conclusions: Coadministration of Ad26.RSV.preF/RSV preF protein and Fluzone-HD showed an acceptable safety profile and did not hamper the immunogenicity of either vaccine, thus supporting that both vaccines can be concomitantly administered in adults ≥65 years old., Competing Interests: Potential conflicts of interest. W. W., C. A. C., and E. H. are former employees of Janssen Vaccines and Prevention B.V.; A. R. B., N. L., and B. C. are employees of Janssen Vaccines and Prevention B.V.; A. M. J. and I. S. are employees of Janssen Research and Development; E. D. P. is a former employee of Janssen Infectious Diseases. 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) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: The aim of the current study was to determine the safety and immunogenicity of trivalent inactivated influenza vaccine (TIV) alone or formulated with Advax delta inulin adjuvant in those who were older (aged >60 years) or had chronic disease., Methods: Over 4 consecutive years from 2008 through 2011, adult participants with chronic disease or >60 years of age were recruited into a randomized controlled study to assess the safety, tolerability and immunogenicity of Advax-adjuvanted TIV (TIV + Adj) versus standard TIV. The per-protocol population with ≥1 postbaseline measurement of influenza antibodies comprised 1297 participants, 447 in the TIV and 850 in the TIV + Adj) group., Results: No safety issues were identified. Variables negatively affecting vaccine responses included obesity and diabetes mellitus. Advax adjuvant had a positive impact on anti-influenza immunoglobulin M responses and on H3N2 and B strain seropositivity as assessed by hemagglutination inhibition., Conclusions: TIV + Adj was safe and well tolerated in individuals with chronic disease. There is an ongoing need for research into improved influenza vaccines for high-risk populations., Clinical Trials Registration: Australia New Zealand Clinical Trial Registry: ACTRN 12608000364370., Competing Interests: Potential conflicts of interest. Y. H. O. and N. P. are affiliated with Vaxine, which holds proprietary rights over Advax adjuvant. 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) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

NT1 is a rare, chronic and disabling neurological disease causing excessive daytime sleepiness and cataplexy. NT1 is characterized pathologically by an almost complete loss of neurons producing the hypocretin (HCRT)/orexin neuropeptides in the lateral hypothalamus. While the exact etiology of NT1 is still unknown, numerous studies have provided compelling evidence supporting its autoimmune origin. The prevailing hypothetical view on the pathogenesis of NT1 involves an immune-mediated loss of HCRT neurons that can be triggered by Pandemrix® vaccination and/or by infection in genetically susceptible patients, specifically carriers of the HLA-DQB1*06:02 MHC class II allele. The molecular mechanisms by which infection/vaccination can induce autoimmunity in the case of NT1 remain to be elucidated. In this review, evidence regarding the involvement of vaccination and infection and the potential mechanisms by which it could be linked to the pathogenesis of NT1 will be discussed in light of the existing findings in other autoimmune diseases., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

Abstract: A 53-year-old woman presented with a pruritic plaque on the left upper arm that appeared following an egg-free flu vaccine due to a history of reaction to the standard vaccine. The affected area enlarged over a several month period immediately following vaccine administration. Physical examination revealed an 8 × 4 cm coalescent pink plaque on the left upper arm. A shave biopsy of the lesion showed dermal "naked" granulomas, or granulomas with sparse lymphocytic infiltrate at the margins, as typically seen in sarcoidosis. No foreign material was seen in the granulomatous reaction, including with polarization. Special stains, including acid fast bacilli, Grocott methenamine silver, periodic acid-Schiff, and Gram, were negative for organisms. The diagnosis of granulomatous dermatitis was made. Subsequent imaging demonstrated no findings suggestive of sarcoidosis. While vaccine-associated hypersensitivity reactions occur frequently, these reactions are typically due to individual vaccine components, such as egg protein, and do not normally result in the formulation of granulomas. Vaccination-induced granulomas are more often associated with the use of aluminum as an adjuvant; however, this is not present in the egg-free influenza vaccine. Thus, a granulomatous reaction to the egg-free influenza vaccine is very unusual and, to our knowledge, not previously reported., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

In the face of global health threats, there is a growing demand for vaccines that can be manufactured on a large scale within compressed timeline. This study responds to this imperative by delving into the evaluation of FluGuard, a novel recombinant influenza vaccine developed by Nivad Pharmed Salamat Company in Iran. Positioned as a phase 3 extension, the research aimed to evaluate the safety and immunogenicity of FluGuard in volunteers aged 18 and above. The study was conducted as a single-center, open-label clinical trial. All eligible volunteers received FluGuard (2021-2022 Formula) on day 0. Safety assessments occurred at days 1, 4, 7, 14, 28 and 42 post-vaccination. Immunogenicity was measured through seroconversion, seroprotection, and geometric mean titer fold increase in subgroups of 250 volunteers. Among the 4,260 volunteers were screened and assessed for eligibility, 1000 were enrolled. At day 28 post-vaccination, seroconversion rates for A/H1N1, A/H3N2, B/Yamagata, B/Victoria were 53.4 % [95 %CI: 46.7-60], 57.7 % [95 %CI: 51.1-64.3], 54.3 % [95 %CI: 47.7-60.9], and 36.2 % [95 %CI: 29.8-42.6], respectively in volunteers 18 years and above. The most common solicited adverse events were pain at the injection site, malaise, and headache. No suspected unexpected adverse events and adverse events of special interest occurred during the study period. Our findings suggested that FluGuard® exhibits a desirable safety profile and provides sufficient immunogenicity against influenza virus types A and B. However, extended studies are warranted to assess the long-term protective efficacy. Trial Registration: The study protocol was accepted by Iranian registry of clinical trial; https://www.irct.ir; IRCT20201104049265N2., 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. Published by Elsevier B.V.)

Objectives: To compare the efficacy of influenza vaccines of any valency for adults 60 years and older., Design and Setting: Systematic review with network meta-analysis (NMA) of randomised controlled trials (RCTs). MEDLINE, EMBASE, JBI Evidence-Based Practice (EBP) Database, PsycINFO, and Cochrane Evidence -Based Medicine database were searched from inception to 20 June 20, 2022. Two reviewers screened, abstracted, and appraised articles (Cochrane Risk of Bias (ROB) 2.0 tool) independently. We assessed certainty of findings using Confidence in Network Meta-Analysis and Grading of Recommendations, Assessment, Development and Evaluations approaches. We performed random-effects meta-analysis and network meta-analysis (NMA), and estimated odds ratios (ORs) for dichotomous outcomes and incidence rate ratios (IRRs) for count outcomes along with their corresponding 95% confidence intervals (CIs) and prediction intervals., Participants: Older adults (≥60 years old) receiving an influenza vaccine licensed in Canada or the USA (vs placebo, no vaccine, or any other licensed vaccine), at any dose., Main Outcome Measures: Laboratory-confirmed influenza (LCI) and influenza-like illness (ILI). Secondary outcomes were the number of vascular adverse events, hospitalisation for acute respiratory infection (ARI) and ILI, inpatient hospitalisation, emergency room (ER) visit for ILI, outpatient visit, and mortality, among others., Results: We included 41 RCTs and 15 companion reports comprising 8 vaccine types and 206 032 participants. Vaccines may prevent LCI compared with placebo, with high-dose trivalent inactivated influenza vaccine (IIV3-HD) (NMA: 9 RCTs, 52 202 participants, OR 0.23, 95% confidence interval (CI) (0.11 to 0.51), low certainty of evidence) and recombinant influenza vaccine (RIV) (OR 0.25, 95%CI (0.08 to 0.73), low certainty of evidence) among the most efficacious vaccines. Standard dose trivalent IIV3 (IIV3-SD) may prevent ILI compared with placebo, but the result was imprecise (meta-analysis: 2 RCTs, 854 participants, OR 0.39, 95%CI (0.15 to 1.02), low certainty of evidence). Any HD was associated with prevention of ILI compared with placebo (NMA: 9 RCTs, 65 658 participants, OR 0.38, 95%CI (0.15 to 0.93)). Adjuvanted quadrivalent IIV (IIV4-Adj) may be associated with the least vascular adverse events, but the results were very uncertain (NMA: eight 8 RCTs, 57 677 participants, IRR 0.18, 95%CI (0.07 to 0.43), very low certainty of evidence). RIV on all-cause mortality may be comparable to placebo (NMA: 20 RCTs, 140 577 participants, OR 1.01, 95%CI (0.23 to 4.49), low certainty of evidence)., Conclusions: This systematic review demonstrated efficacy associated with IIV3-HD and RIV vaccines in protecting older persons against LCI. RIV vaccine may reduce all-cause mortality when compared with other vaccines, but the evidence is uncertain. Differences in efficacy between influenza vaccines remain uncertain with very low to moderate certainty of evidence., Prospero Registration Number: CRD42020177357., 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.)

Abstract: Annual seasonal influenza epidemics cause substantial disease and economic burden worldwide. During the coronavirus disease 2019 (COVID-19) pandemic in 2020 and 2021, influenza activity significantly declined. However, influenza resurged in Australia following the relaxation of non-pharmaceutical interventions, with increased influenza virus circulation in early 2022 coinciding with the SARS-CoV-2 Omicron BA.2 variant wave. Together with other respiratory virus diseases, these disease impacts on the Australian population and healthcare system have re-emphasised the importance of influenza vaccination and control. We aim to provide an overview of the current seasonal influenza vaccination program in Australia and summarise evidence and considerations underpinning potential future immunisation strategies. Influenza causes disproportionately higher morbidity and mortality in young children and older adults. Other populations at elevated risk from influenza include Aboriginal and Torres Strait Islander peoples, pregnant women, and people with certain underlying medical conditions. All Australians aged ≥ 6 months are recommended to receive influenza vaccine every year. The National Immunisation Program (NIP) provides free vaccine for eligible at-risk populations. While approximately 70% of older adults had received influenza vaccine in 2022, coverage in other age groups remains suboptimal. There are several key unmet needs and challenges, but also potential strategies for enhancing the influenza vaccination program in Australia. Improved monitoring and evaluation, including the use of relevant linked datasets for such purposes, is imperative to better understand variations in coverage and vaccination impact in specific populations. Adoption of evidence-based strategies, such as culturally appropriate resources that consider the characteristics of diverse Australian populations, may also help to achieve higher vaccine coverage rates. Additionally, greater vaccine uptake across the population could be facilitated by expanding the NIP-eligible population where cost-effective, and adopting the use of more effective and different types of vaccines when available., (© Commonwealth of Australia CC BY-NC-ND.)

Objective: To evaluate background incidence rates of 59 health outcomes of interest (HOI) in a diverse population, including important subpopulations, during the pre-COVID-19 era (1 January 2017-31 December 2019) and the COVID-19 era (1 March 2020-31 December 2020), before the introduction of COVID-19 vaccines., Design: Observational retrospective cohort study. Annual incidence rates and 95% confidence intervals (CIs) of HOIs were estimated for each population of interest, stratified by: age, sex, age and sex and seasonality., Data Source: Optum's de-identified Clinformatics Data Mart Database (CDM)., Participants: Individuals from the US general population and four subgroups of interest: influenza-vaccinated, paediatric (<18 years of age), elderly (≥65 years of age) and pregnant women., Results: During the COVID-19 era, the incidence of several cardiac conditions, coagulation disorders and acute liver injury increased across all populations assessed while the rates of some dermatological and neurological HOIs decreased relative to the pre-COVID-19 era. The incidence of acute respiratory distress syndrome (ARDS) varied considerably by subgroup: among the elderly, it decreased annually during the pre-COVID-19 era but peaked during the COVID-19 era; among pregnant women, it slightly increased annually during the pre-COVID-19 era and substantially increased during the COVID-19 era; among paediatrics, it decreased annually over the entire study. The incidence of the majority of HOIs increased with age, but were generally comparable between sexes with few exceptions. Cardiac, gastrointestinal, neurological and haematological HOIs, along with acute kidney injury and ARDS, were more common in males, whereas several immunological HOIs and chilblain-like lesions were more common in females. Pregnancy-related HOIs did not increase during the COVID-19 era, except for spontaneous abortions which increased annually over the entire study., Conclusion: These observations help contextualise fluctuations in background rates of adverse events noted during the COVID-19 era, and provide insight on how their use may impact safety surveillance for other vaccines., Competing Interests: Competing interests: SB, AK, LS, A-LC and CP are employees of Sanofi and may hold shares and/or stock options in the company. IE, SS and HK are employees of Aetion and hold stock options in the company., (© 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.)

Objective: To investigate (1) the UK-wide inactivated influenza vaccine (IIV) uptake in adults with inflammatory bowel disease (IBD), (2) the association between vaccination against influenza and IBD flare and (3) the effectiveness of IIV in preventing morbidity and mortality., Design: Data for adults with IBD diagnosed before the 1 September 2018 were extracted from the Clinical Practice Research Datalink Gold. We calculated the proportion of people vaccinated against seasonal influenza in the 2018-2019 influenza cycle. To investigate vaccine effectiveness, we calculated the propensity score (PS) for vaccination and conducted Cox proportional hazard regression with inverse-probability treatment weighting on PS. We employed self-controlled case series analysis to investigate the association between vaccination and IBD flare., Results: Data for 13 631 people with IBD (50.4% male, mean age 52.9 years) were included. Fifty percent were vaccinated during the influenza cycle, while 32.1% were vaccinated on time, that is, before the seasonal influenza virus circulated in the community. IIV was associated with reduced all-cause mortality (aHR (95% CI): 0.73 (0.55,0.97) but not hospitalisation for pneumonia (aHR (95% CI) 0.52 (0.20-1.37), including in the influenza active period (aHR (95% CI) 0.48 (0.18-1.27)). Administration of the IIV was not associated with IBD flare., Conclusion: The uptake of influenza vaccine was low in people with IBD, and the majority were not vaccinated before influenza virus circulated in the community. Vaccination with the IIV was not associated with IBD flare. These findings add to the evidence to promote vaccination against influenza in people with IBD., Competing Interests: Competing interests: AA has received personal fees from UpToDate (royalty), Cadilla Pharmaceuticals (lecture fees), NGM Bio (consulting), Limbic (consulting) and Inflazome (consulting) unrelated to this work. CDM is the director of the NIHR School for Primary Care Research. Keele University has received research funding for CDM from NIHR, MRC, Versus Arthritis and BMS. JSN-V-T was seconded to the Department of Health and Social Care (DHSC) from October 2017 to March 2022. Since March 2022, he has received personal fees from CSL Seqirus (lectures, writing and consulting), AstraZeneca (lecture) and Sanofi Pasteur (lectures and speaking), all of whom manufacture influenza vaccines. He consults for Moderna Therapeutics who are developing influenza vaccines. The views expressed in this manuscript are those of its authors and not necessarily those of DHSC or any other entity mentioned above. The other authors have no conflict of interest to declare, (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Introduction: Active and passive surveillance studies have found that a greater proportion of females report adverse events (AE) following receipt of either the COVID-19 or seasonal influenza vaccine compared to males. In a predominately young adult female population of healthcare workers, we sought to determine the intersection of biological sex and sociocultural gender differences in prospective active reporting of vaccine outcomes, which remains poorly characterized., Methods: This cohort study enrolled Johns Hopkins Health System healthcare workers (HCWs) who were recruited from the mandatory annual fall 2019-2022 influenza vaccine and the fall 2022 COVID-19 bivalent vaccine campaigns. Vaccine recipients were enrolled the day of vaccination and AE surveys were administered two days post-vaccination for bivalent COVID-19 and influenza vaccine recipients. Data were collected regarding the presence of a series of solicited local and systemic AEs. Open-ended answers about participants' experiences with AEs also were collected for the COVID-19 vaccine recipients., Results: Females were more likely to report local AEs after either influenza (OR = 2.28, p = 0.001) or COVID-19 (OR = 2.57, p = 0.008) vaccination compared to males, regardless of age or race. Males and females had comparable probabilities of reporting systemic AEs after either influenza (OR = 1.18, p = 0.552) or COVID-19 (OR = 0.96, p = 0.907) vaccination. Hormonal birth control use did not impact the rates of reported AEs following influenza vaccination among reproductive-aged female HCWs. Women reported more interruptions in their daily routine following COVID-19 vaccination than men and were more likely to seek out self-treatment. More women than men scheduled their COVID-19 vaccination before their days off in anticipation of AEs., Conclusions: Our findings highlight the need for sex- and gender-inclusive policies to inform more effective mandatory occupational health vaccination strategies. Further research is needed to evaluate the potential disruption of AEs on occupational responsibilities following mandated vaccination for healthcare workers, a predominately female population, and to more fully characterize the post-vaccination behavioral differences between men and women., (© 2024. The Author(s).)

Introduction: A surge of human influenza A(H7N9) cases began in 2016 in China from an antigenically distinct lineage. Data are needed about the safety and immunogenicity of 2013 and 2017 A(H7N9) inactivated influenza vaccines (IIVs) and the effects of AS03 adjuvant, prime-boost interval, and priming effects of 2013 and 2017 A(H7N9) IIVs., Methods: Healthy adults (n = 180), ages 19-50 years, were enrolled into this partially blinded, randomized, multicenter phase 2 clinical trial. Participants were randomly assigned to 1 of 6 vaccination groups evaluating homologous versus heterologous prime-boost strategies with 2 different boost intervals (21 vs 120 days) and 2 dosages (3.75 or 15 μg of hemagglutinin) administered with or without AS03 adjuvant. Reactogenicity, safety, and immunogenicity measured by hemagglutination inhibition and neutralizing antibody titers were assessed., Results: Two doses of A(H7N9) IIV were well tolerated, and no safety issues were identified. Although most participants had injection site and systemic reactogenicity, these symptoms were mostly mild to moderate in severity; injection site reactogenicity was greater in vaccination groups receiving adjuvant. Immune responses were greater after an adjuvanted second dose, and with a longer interval between prime and boost. The highest hemagglutination inhibition geometric mean titer (95% confidence interval) observed against the 2017 A(H7N9) strain was 133.4 (83.6-212.6) among participants who received homologous, adjuvanted 3.75 µg + AS03/2017 doses with delayed boost interval., Conclusions: Administering AS03 adjuvant with the second H7N9 IIV dose and extending the boost interval to 4 months resulted in higher peak antibody responses. These observations can broadly inform strategic approaches for pandemic preparedness. Clinical Trials Registration. NCT03589807., Competing Interests: Potential conflicts of interest . E. J. A. has consulted for Pfizer, Sanofi Pasteur, GSK, Janssen, Moderna, and Medscape, and his institution has received funds to conduct clinical research unrelated to this manuscript from MedImmune, Regeneron, PaxVax, Pfizer, GSK, Merck, Sanofi-Pasteur, Janssen, and Micron. He has served on a safety monitoring board for Kentucky BioProcessing, Inc. and Sanofi Pasteur. He has served on a data adjudication board for WCG and ACI Clinical. His institution has also received funding from the National Institutes of Health (NIH) to conduct clinical trials of COVID-19 vaccines. He is currently employed by Moderna, Inc. N. R. has consulted for EMMES, Moderna, GSK, Sanofi, Seqirus, and ICON, and her institution receives funds to conduct clinical research unrelated to this manuscript from Pfizer, Sanofi, Quidel, Lilly, Immorna, Vaccine Company, and Merck as well as NIH to conduct translational clinical studies and interventional clinical trials. P. W. has consulted for EMMES and Pfizer and her institution has received funds to conduct clinical research unrelated to this manuscript from Pfizer, Glaxo Smith Kline, Sanofi-Pasteur, and Gilead as well as NIH. C. A. R.'s institution has received funds to conduct clinical research unrelated to this manuscript from the Centers for Disease Control and Prevention, BioFire Inc, GSK, MedImmune, Janssen, Merck, Moderna, Novavax, PaxVax, Pfizer, Regeneron, and Sanofi-Pasteur. She is co-inventor of patented respiratory syncytial virus vaccine technology, which has been licensed to Meissa Vaccines, Inc. C. M. K.'s institution has received funds to conduct clinical research unrelated to this manuscript from the CDC, Pfizer, Merck, and the NIH to conduct clinical trials of the Moderna COVID-19 vaccine. V. R. is currently employed by Pfizer, Inc., and works in vaccine clinical research unrelated to the current manuscript. This material reflects the personal views of the author and may not reflect the views of her current employer. M. J. M. reported these potential competing interests: laboratory research and clinical trials contracts for vaccines or MAB with Lilly, Pfizer, and Sanofi; contract funding from USG/HHS/BARDA for research specimen characterization and repository; research grant funding from USG/HHS/NIH for vaccine and MAB clinical trials; personal fees for Scientific Advisory Board service from Merck, Meissa Vaccines, Inc., and Pfizer. EBW has received funding support from Pfizer, Moderna, Sequiris, Najit Technologies Inc, and Clinetic for the conduct of clinical trials and clinical research. E. B. W. has served as an advisor to Vaxcyte and consultant to ILiAD biotechnologies. A. C. S.'s institution has received funds to conduct clinical research unrelated to this manuscript from NIH, HIV Vaccine Trials Network, COVID Vaccine Prevention Network, International AIDS Vaccine Initiative, Crucell/Janssen, Moderna, Pfizer, and Sanofi-Pasteur. S. K.'s institution has received funds to conduct clinical research and vaccine trials unrelated to this manuscript from the CDC, Pfizer, Meissa, Emergent BioSolutions, and the NIH. I. Y. reported being a member of the NIAID/COVPN mRNA-1273 Study Group and her institution received funding to conduct clinical research from NIH, Gates Foundation, Centers for Disease Control and Prevention, Pfizer, and Moderna outside the submitted work. She has consulted for Merck, Sanofi-Pasteur, and UptoDate. S. E. F. has received funding to conduct research from Novartis, Moderna, Janssen, Pfizer, and Bavarian Nordic and is a member of the HIV Vaccine Trials Network safety monitoring board. G. A. has received funding to conduct research from Bavarian Nordic. 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. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: The MIMIX platform is a novel microneedle array patch (MAP) characterized by slowly dissolving microneedle tips that deploy into the dermis following patch application. We describe safety, reactogenicity, tolerability and immunogenicity for MIMIX MAP vaccination against influenza., Methodology: The trial was a Phase 1, exploratory, first-in-human, parallel randomized, rater, participant, study analyst-blinded, placebo-controlled study in Canada. Forty-five healthy participants (18 to 39 years of age, inclusive) were randomized in a 1:1:1 ratio to receive either 15 μg or 7.5 μg of an H1N1 influenza vaccine, or placebo delivered via MIMIX MAP to the volar forearm. A statistician used a computer program to create a randomization scheme with a block size of 3. Post-treatment follow-up was approximately 180 days. Primary safety outcomes included the incidence of study product related serious adverse events and unsolicited events within 180 days, solicited application site and systemic reactogenicity through 7 days after administration and solicited application site erythema and/or pigmentation 14, 28, 56 and 180 days after administration. Immunogenicity outcomes included antibody titers and percentage of seroconversion (SCR) and seroprotection (SPR) rates determined by the hemagglutination inhibition (HAI) assay. Exploratory outcomes included virus microneutralization (MN) titers, durability and breadth of the immune response. The trial was registered with ClinicalTrials.gov, number NCT06125717., Findings: Between July 7, 2022 and March 13, 2023 45 participants were randomized to a treatment group. One participant was lost to follow up in the 15 μg group and 1 participant withdrew from the 7.5 μg dose group. Safety analyses included n = 15 per group, immunogenicity analyses included n = 14 for the 15 μg and 7.5 μg treatment groups and n = 15 for the placebo group. No SAEs were reported in any of the treatment groups. All treatment groups reported solicited local events within 7 days after vaccination, with mild (Grade 1) erythema being the most frequent symptom reported. Other local symptoms reported included mostly mild (Grade 1) induration/swelling, itching, pigmentation, skin flaking, and tenderness. Within 7 days after vaccination, 2 participants (4.4%) reported moderate (Grade 2) erythema, 1 participant (2.2%) reported moderate (Grade 2) induration/swelling, and 1 participant (2.2%) reported moderate (Grade 2) itching. There was an overall reduction in erythema and pigmentation reported on Days 15, 29, 57, and 180 among all treatment groups. Systemic symptoms reported within 7 days after vaccination, included mild (Grade 1) fatigue reported among all treatment groups, and mild (Grade 1) headache reported by 1 participant in the 7.5 μg treatment group. No study drug related severe symptoms were reported in the study. Group mean fold rises in HAI titers ranged between 8.7 and 12-fold, SCRs were >76% and SPRs were >92% for both VX-103 dose groups thereby fulfilling serological criteria established by the EMA and FDA for seasonal influenza vaccines. Longitudinal assessments demonstrate persistence of the immune response through at least Day 180., Conclusions: The MIMIX MAP platform is safe, well tolerated and elicits robust antibody responses., Competing Interests: Jon Kluge, Jonathan L. Portman, Anna Markowska and Lynda Tussey are employees of the clinical trial sponsor Vaxess Technologies. Naveen Garg, Guy Tellier and Noah Vale are employees of Centricity Research, the clinical research organization responsible for conducting the VX103-01 clinical trial. All Vaxess related patent information is included below. These competing interests do not impact the authors adherence to PLOS ONE policies and data sharing. Country Application No. Publication No Application Title US 17/714025 US-2022-0339416-A1 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF WO PCT/US2020/055139 WO 2021/072313 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF AU 2020364146 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF CA 3156676 3156676 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF CN 202080071018.4 114728154 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF EP 20874211.4 4041330 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF JP 2022-521636 2022-551910 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF KR 10-2022-7014919 10-2022-0093120 SILK FIBROIN-BASED MICRONEEDLES AND USES THEREOF US 17/958148 US-2023-0190911-A1 VACCINE FORMULATIONS WITH INCREASED STABILITY WO PCT/US2017/052301 WO 2018/053524 VACCINE FORMULATIONS WITH INCREASED STABILITY AU 2017327009 2017327009 VACCINE FORMULATIONS WITH INCREASED STABILITY CA 3037337 3037337 VACCINE FORMULATIONS WITH INCREASED STABILITY EP 17778047.5 3532093 VACCINE FORMULATIONS WITH INCREASED STABILITY US 17/157451 US-2021-0283597-A1 POLYMER-BASED BIOSPECIMEN COLLECTION DEVICES AND USES THEREOF WO PCT/US2019/043727 WO 2020/023906 POLYMER-BASED BIOSPECIMEN COLLECTION DEVICES AND USES THEREOF EP 19761984.4 3830576 POLYMER-BASED BIOSPECIMEN COLLECTION DEVICES AND USES THEREOF US 17/044439 US-2021-0085598-A1 MICRONEEDLE COMPRISING SILK FIBROIN APPLIED TO A DISSOLVABLE BASE WO PCT/US2019/025467 WO 2019/195350 MICRONEEDLE COMPRISING SILK FIBROIN APPLIED TO A DISSOLVABLE BASE AU 2019247655 MICRONEEDLE COMPRISING SILK FIBROIN APPLIED TO A DISSOLVABLE BASE CA 3096036 3096036 MICRONEEDLE COMPRISING SILK FIBROIN APPLIED TO A DISSOLVABLE BASE EP 19718034.2 3773477 MICRONEEDLE COMPRISING SILK FIBROIN APPLIED TO A DISSOLVABLE BASE WO PCT/US2023/026036 WO 2023/250117 APPLICATOR FOR MEDICAMENT PATCH US 17/991525 US-2023-0270842-A1 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF WO PCT/US2021/033776 WO 2021/237174 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF AU 2021276000 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF CA 3183930 3183930 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF CN 202180061194.4 CN116406285A COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF EP 21809075.1 4153139 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF JP 2022-571231 2023-527175 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF KR 10-2022-7044731 COMPOSITIONS AND DEVICES FOR VACCINE RELEASE AND USES THEREOF US 18/563337 MICRONEEDLE VACCINE AGAINST SEVERE ACUTE RESPIRATORY SYNDROME CORONAVIRUS 2 (SARS-COV-2), (Copyright: © 2024 Garg 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: During the 2022-23 season, three autonomous communities recommended influenza vaccination for all children between 6 and 59 months. The objective is to evaluate the adverse effects associated with the administered influenza vaccines in the Region of Murcia, as well as their influence on the recommendation of the same to acquaintances or repetition in future seasons., Material and Methods: Cross-sectional descriptive study with an online questionnaire sent to the parents of vaccinated minors of 6-23 months of age receiving inactivated intramuscular vaccine (IIV) or 24-59 months of age receiving live-attenuated intranasal vaccine (LAIV)., Results: Among 4971 surveys received, the most common adverse effect for LAIV and IIV was runny nose (40.90%) and local pain (31.94%), respectively. Sixty percent of adverse effects lasted ≤ 1 day, and around 10% lasted ≥ 3 days. The interference of adverse effects with the minor's daily life was very infrequent (3.32%), as was the need for visiting the medical office (2.68%). Overall, 96.44% of parents would recommend influenza vaccination to friends and relatives after the experience. Only 3.56% would not recommend it, while 1.68% would not vaccinate their child against influenza again. The most frequently cited reason being adverse effects., Conclusions: Our study shows the safety of influenza vaccines. Despite the low impact of adverse effects, they influence some parents in their intention to continue vaccinating or recommending it to acquaintances, which remarks the need to reinforce the information given to parents so that this fact does not influence decision-making., (© 2024 The Author(s). Influenza and Other Respiratory Viruses published by John Wiley & Sons Ltd.)

Due to the limitation of previous studies examining adverse reports of myocarditis and pericarditis associated with vaccines other than the COVID-19 vaccine, there are challenges in establishing a comprehensive understanding of vaccine safety on a global scale. Hence, the objective of this study was to examine the worldwide burden of vaccine-associated pericarditis and myocarditis and the vaccines associated with these indications. This study utilized the World Health Organization international pharmacovigilance database, from which records of vaccine-associated pericarditis and myocarditis between 1969 and 2023 were extracted (over 130 million reports). We calculated global reporting counts, reported odds ratios (RORs), and information components (ICs) to discern the association between 19 vaccines and the occurrence of pericarditis and myocarditis across 156 countries and territories. We identified 49 096 reports (male, n = 30 013) of vaccine-associated pericarditis and myocarditis among 73 590 reports of all-cause pericarditis and myocarditis. There has been a significant increase in reports of vaccine-related cardiac adverse events over time, with a noteworthy surge observed after 2020, attributed to cases of pericarditis associated with COVID-19 mRNA vaccines. Smallpox vaccines were associated with most pericarditis and myocarditis reports (ROR: 73.68 [95% CI, 67.79-80.10]; IC [IC 0.25 ]: 6.05 [5.91]), followed by COVID-19 mRNA vaccine (37.77 [37.00-38.56]; 3.07 [3.05]), anthrax vaccine (25.54 [22.37-29.16]; 4.58 [4.35]), typhoid vaccine (6.17 [5.16-7.38]; 2.59 [2.29]), encephalitis vaccine (2.00 [1.48-2.71]; 0.99 [0.47]), influenza vaccine (1.87 [1.71-2.04]; 0.90 [0.75]), and Ad5-vectored COVID-19 vaccine (1.40 [1.34-1.46]; 0.46 [0.39]). Concerning age and sex-specific risks, reports of vaccine-associated pericarditis and myocarditis were more prevalent among males and in older age groups. The age group between 12 and 17 years exhibited significant sex disproportion. Most of these adverse events had a short time to onset (median time: 1 day) and fatality rate was 0.44%. Our analysis of global data revealed an increase in pericarditis and myocarditis reports associated with vaccines, particularly live vaccines like smallpox and anthrax, notably in young males. While these adverse events are generally rare and mild, caution is warranted, especially for healthcare workers, due to potential myocardial injury-related in-hospital mortality. Further study with validated reporting is crucial to enhance accuracy in evaluating the correlation between vaccines and cardiac conditions for preventive measures., (© 2024 Wiley Periodicals LLC.)

Background: While safety of influenza vaccines is well-established, some studies have suggested potential associations between influenza vaccines and certain adverse events (AEs). This study examined the safety of the 2022-2023 influenza vaccines among U.S. adults ≥ 65 years., Methods: A self-controlled case series compared incidence rates of anaphylaxis, encephalitis/encephalomyelitis, Guillain-Barré Syndrome (GBS), and transverse myelitis following 2022-2023 seasonal influenza vaccinations (i.e., any, high-dose or adjuvanted) in risk and control intervals among Medicare beneficiaries ≥ 65 years. We used conditional Poisson regression to estimate incidence rate ratios (IRRs) and 95 % confidence intervals (CIs) adjusted for event-dependent observation time and seasonality. Analyses also accounted for uncertainty from outcome misclassification where feasible. For AEs with any statistically significant associations, we stratified results by concomitant vaccination status., Results: Among 12.7 million vaccine recipients, we observed 76 anaphylaxis, 276 encephalitis/encephalomyelitis, 134 GBS and 75 transverse myelitis cases. Only rates of anaphylaxis were elevated in risk compared to control intervals. With all adjustments, an elevated, but non-statistically significant, anaphylaxis rate was observed following any (IRR: 2.40, 95% CI: 0.96-6.03), high-dose (IRR: 2.31, 95% CI: 0.67-7.91), and adjuvanted (IRR: 3.28, 95% CI: 0.71-15.08) influenza vaccination; anaphylaxis IRRs were 2.54 (95% CI: 0.49-13.05) and 1.64 (95% CI: 0.38-7.05) for persons with and without concomitant vaccination, respectively., Conclusions: Rates of encephalitis/encephalomyelitis, GBS, or transverse myelitis were not elevated following 2022-2023 seasonal influenza vaccinations among U.S. adults ≥ 65 years. There was an increased rate of anaphylaxis following influenza vaccination that may have been influenced by concomitant 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. Published by Elsevier Ltd.)

Introduction: Acquired hemophilia-A (AHA) is a rare but potentially life-threatening impaired coagulation disorder characterized by the development of autoantibodies against clotting factor VIII. Only a few case reports have been experienced with influenza vaccine-triggered AHA. Here, we report a case of severe hemorrhagic disorder due to AHA following influenza vaccine, which was successfully treated., Patient Concerns: The patient presented to the emergency department because of several severe, progressively worsening bruises after receiving the influenza vaccination. Consequently, the patient required intubation due to nasal-oral bleeding, which compromised the airway, and retroperitoneal hemorrhage with shock also developed., Diagnosis: AHA was confirmed through a coagulation factor assay, including coagulation activity and antibody testing, which is possibly triggered by influenza vaccination., Intervention: Low-dose cyclophosphamide and hydrocortisone were prescribed until activated partial thromboplastin time showed normal levels. Coagulation factor VIIa was administered, and aggressive blood transfusion was carried out concurrently to address the blood loss., Outcomes: The upper airway bleeding subsided and bleeding tendencies had been corrected to normal. The patient was smoothly weaned from the ventilator and recovered from critical illness. She was then discharged on the 19th day., Lessons: The activated partial thromboplastin time mixing test can be performed immediately to establish the initial differential diagnosis and treatment plan for severe coagulopathy. AHA may be triggered by vaccination, with the hypothesis of activation of autoantibodies and molecular mimicry; this mechanism should be further studied., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Respiratory syncytial virus (RSV) and influenza are both typically seasonal diseases, with winter peaks in temperate climates. Coadministration of an RSV vaccine and influenza vaccine could be a benefit, requiring 1 rather than 2 visits to a healthcare provider for individuals receiving both vaccines., Methods: The primary immunogenicity objective of this phase 3, 1:1 randomized, double-blind, placebo-controlled study in healthy adults aged ≥65 years in Australia was to demonstrate noninferiority of immune responses with coadministration of the stabilized RSV prefusion F protein-based vaccine (RSVpreF) and seasonal inactivated influenza vaccine (SIIV) versus SIIV or RSVpreF administered alone, using a 1.5-fold noninferiority margin (lower bound 95% confidence interval >.667). Safety and tolerability were evaluated by collecting reactogenicity and adverse event data., Results: Of 1403 participants randomized, 1399 received vaccinations (median age, 70; range, 65‒91 years). Local reactions and systemic events were mostly mild or moderate when RSVpreF was coadministered with SIIV or administered alone. No vaccine-related serious adverse events were reported. Geometric mean ratios were 0.86 for RSV-A and 0.85 for RSV-B neutralizing titers at 1 month after RSVpreF administration and 0.77 to 0.90 for strain-specific hemagglutination inhibition assay titers at 1 month after SIIV. All comparisons achieved the prespecified 1.5-fold noninferiority margin., Conclusions: The primary study objectives were met, demonstrating noninferiority of RSVpreF and SIIV immune responses when RSVpreF was coadministered with SIIV and that RSVpreF had an acceptable safety and tolerability profile when coadministered with SIIV. The results of this study support coadministration of RSVpreF and SIIV in an older-adult population., Clinical Trials Registration: https://clinicaltrials.gov/study/NCT05301322., Competing Interests: Potential conflicts of interest. E. A. reports receiving consulting fees from Moderna for vaccine advisory meeting. R. J. S. reports being an investigator for Pfizer (consultant doctor/medical investigator for the University of the Sunshine Coast Clinical Trials team; received consulting fees to work as a medical investigator; and was involved with the conduct of the clinical trial for Pfizer RSVpreF vaccine at the clinical trial site in Queensland, Australia). A. G. reports patents planned, issued, or pending: WO2017/1096729. All authors (except E. A. and R. J. S.) are employees of Pfizer, Inc, and may hold stock or stock options. 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) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Influenza, pneumococcal, severe acute respiratory syndrome coronavirus 2, and respiratory syncytial virus infections are important causes of high morbidity and mortality in the elderly. Beyond the burden of infectious diseases, they are also associated with several non-infectious complications like cardiovascular events. A growing body of evidence in prospective studies and meta-analyses has shown the impact of influenza and pneumococcal vaccines on types of cardiovascular outcomes in the general population. Influenza vaccination showed a potential benefit for primary and secondary prevention of cardiovascular diseases across all ages. A reduced risk of cardiovascular events for individuals aged 65 years and older was associated with pneumococcal vaccination. Despite scientific evidence on the effectiveness, safety, and benefits of the vaccines and recommendations to vaccinate elderly patients and those with risk factors, vaccination rates remain sub-optimal in this population. Doubts about vaccine necessity or efficacy and concerns about possible adverse events in patients and physicians refer to delayed acceptance. Vaccination campaigns targeting increasing professional recommendations and public perceptions should be implemented in the coming years. The aim of this review paper is to summarize the effect of vaccination in the field of cardiovascular disease to achieve a higher vaccination rate in this patient population., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The current recommendation for the elderly is to receive both a single dose 23-valent pneumococcal polysaccharide vaccine (PPSV-23) and an annual inactivated influenza vaccine. There is a lack of post-marketing safety studies on concomitant vaccination using real-world data. We aimed to evaluate the safety of administering PPSV-23 and influenza vaccine concomitantly versus sequentially., Methods: We performed a retrospective cohort study using a linked database that combines vaccination registry from the Korea Disease Control and Prevention Agency and claims data from the National Health Insurance Service. The study population included all those aged over 65 who received PPSV-23 at least once from Jan 1, 2016, to Dec 31, 2020. This study evaluated the 16 prespecified events of interest. Concomitant vaccination was defined as receiving both PPSV-23 and influenza vaccine on the same day. For sequential vaccination, we defined it as receiving influenza vaccination during the period from 30 to 365 days prior to the date of PPSV-23 injection. We performed 1:4 propensity score matching and estimated adjusted incidence rate ratio (aIRR) with a 95 % confidence interval (CI) using conditional Poisson regression., Results: Of the 2,885,144 elderly patients who received PPSV-23 vaccination at least once from Jan 1, 2016, to Dec 31, 2020, a total 87,899 were included in the concomitant vaccination group and 1,200,091 were included in the sequential vaccination group. After adjusting for confounders, the concomitant group exhibited a significantly lower risk of allergic reactions (aIRR: 0.71, 95 % CI: 0.58-0.87), neuritis (aIRR: 0.72, 95 % CI: 0.57-0.91), and pneumonia (aIRR: 0.85, 95 % CI: 0.80-0.90), while demonstrating significantly higher risks of paralysis (aIRR: 1.63, 95 % CI: 1.05-2.52) compared to the sequential group., Conclusions: Concomitant administration of PPSV-23 and influenza vaccine in the elderly was not associated with a higher risk of most prespecified adverse events (AEs) compared to sequential vaccination. This study supports the safety of concomitant administration of PPSV-23 and influenza vaccine., 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.)

Objectives: Concomitant COVID-19 and influenza vaccination would be an efficient strategy. Although the co-administration of monovalent COVID-19 and influenza vaccinations showed acceptable immunogenicity, it remains unknown whether the bivalent COVID-19 vaccine could intensify immune interference. We aimed to evaluate the immunogenicity and safety of concomitant BA.5-based bivalent COVID-19 and influenza vaccination., Methods: An open-label, nonrandomized clinical trial was conducted for 154 age-matched and sex-matched healthy adults between October 2022 and December 2022. Participants received either a concomitant bivalent COVID-19 mRNA booster and quadrivalent influenza vaccination (group C) or separate vaccinations (group S) at least 4 weeks apart. Solicited and unsolicited adverse events were reported up to 6 months postvaccination. Immunogenicity was evaluated by anti-spike (S) IgG electrochemiluminescence immunoassay, focus reduction neutralization test, and hemagglutination inhibition assay., Results: Group C did not meet the noninferiority criteria for the seroconversion rates of anti-S IgG and neutralizing antibodies against the wild-type SARS-CoV-2 strain compared with group S (44.2% vs. 46.8%, difference of -2.6% [95% CI, -18 to 13.4]; 44.2% vs. 57.1%, difference of -13.0% [95% CI to -28.9 to 2.9]). However, group C showed a stronger postvaccination neutralizing antibody response against Omicron BA.5 (72.7% vs. 64.9%). Postvaccination geometric mean titers for SARS-CoV-2 and influenza strains were similar between groups, except for influenza B/Victoria. Most adverse events were mild and comparable between the study groups., Discussion: Concomitant administration of bivalent COVID-19 mRNA and quadrivalent influenza vaccines showed tolerable safety profiles and sufficient immunogenicity, particularly attenuating immune imprinting induced by previous ancestral vaccine strains., (Copyright © 2024 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Introduction: Bivalent mRNA coronavirus disease 2019 (COVID-19) vaccines may be simultaneously administered with other recommended vaccines, including seasonal influenza vaccines. However, few studies have evaluated the safety of co-administration of bivalent mRNA COVID-19 and seasonal influenza vaccines., Objective: The aim was to describe reports to the Vaccine Adverse Event Reporting System (VAERS) after co-administration of bivalent mRNA COVID-19 and seasonal influenza vaccines., Methods: We searched the VAERS database for reports of adverse events (AEs) following co-administration of bivalent mRNA COVID-19 and seasonal influenza vaccines during the period of September 1, 2022-March 31, 2023. We assessed the characteristics of these reports and described the most frequently reported AEs. Clinicians reviewed available medical records for reports of serious AEs and adverse events of special interest (AESI)., Results: During the period of 1 September 2022 through 31 March 2023, VAERS received 3689 reports of AEs following co-administration of bivalent mRNA COVID-19 and seasonal influenza vaccines. The median age of vaccinees was 59 years (interquartile range 39, 70 years); 342 reports (9.3%) were classified as serious. The most common AEs among non-serious reports were severe-acute-respiratory-syndrome-related coronavirus (SARS-CoV-2) infection (785, 23.5%), cough (592, 17.7%), and fatigue (568, 17.0%). The most common AEs among serious reports were Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (88, 25.7%), dyspnea (81, 23.7%), and condition aggravated (55, 16.1%)., Discussion: Reports of AEs following co-administration of bivalent mRNA COVID-19 and seasonal influenza vaccines did not reveal any unusual or unexpected patterns of AEs. Increased reporting of certain events (e.g., COVID-19) was expected due to Food and Drug Administration (FDA) and Centers for Disease Control and Prevention (CDC) reporting requirements. CDC and FDA will continue to monitor the safety of co-administration of mRNA COVID-19 and seasonal influenza vaccines., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)