Background Increased transmission of avian influenza from animals to humans has elevated the risk of an H5 pandemic. Methods This phase 2, randomized, observer-blind, multi-center trial assessed the immunogenicity and safety of homologous priming with an MF59-adjuvanted, cell-based H5N8 A/Astrakhan/3212/2020 clade 2.3.4.4b vaccine (aH5N8c). We enrolled adults age ≥18 years, equally stratified into 18–64 (including a poultry-worker subset) and ≥65 year cohorts. Primary and secondary outcomes were homologous antibody responses against H5N8 measured in all participants by hemagglutination inhibition (HI) and in a subset by microneutralization (MN) assays on Days 1, 22, and 43. Solicited adverse events (AEs) were monitored for 7 days post-vaccination, with unsolicited AEs tracked throughout Day 43. Results 239 participants were vaccinated (18–64 years, n = 121; ≥65 years, n = 118). At Day 43 (21 days post second aH5N8c dose), geometric mean fold increases (GMFI) were 13.7 for the 18–64 cohort and 10.2 for the ≥65 cohort. HI seroconversion rates were 75.8% (95% CI 66.1–83.8%) for the 18–64 cohort and 71.0% (61.1–79.6%) for the ≥65 cohort. HI titers ≥1:40 were achieved in 75.8% (66.1–83.8%) and 73.0% (63.2–81.4%) of participants, respectively. MN seroconversion rates were 80.6% (68.6–89.6%) and 70.0% (56.8–81.2%), while MN titers ≥1:40 were 83.9% (72.3–92.0%) and 86.7% (75.4–94.1%), respectively. No notable differences in immune responses by poultry worker status were observed. Most solicited AEs were mild or moderate, resolving within 3 days. Unsolicited AEs were reported by 16.7% participants by Day 43. Conclusion These data support the use of the MF59-adjuvanted, cell-based monovalent H5N8 vaccine as a public health intervention against H5 influenza.
Introduction Pertussis vaccination is recommended for all pregnant women in England. Uptake remains suboptimal, with regional and demographic variability, leaving neonates at risk. This persists despite expansion of vaccine provision across maternity services since 2017. This study aimed to identify determinants of inequity and opportunities for intervention. Methods Cross-sectional online surveys of: ii) 551 maternity healthcare professionals (HCPs), comparing those working in trusts within the highest- and lowest-vaccinating regions of England. i) 377 mothers of young babies from lowest-vaccinating regions, comparing women vaccinated versus unvaccinated against pertussis in their recent pregnancy; and Questionnaires were informed by the COM-B framework. Logistic regression modelling assessed factors associated with vaccination, alongside content analysis of free-text responses. Results i) HCP survey: Area-level deprivation was strongly associated with low-vaccinating regions. Controlling for this, low-vaccinating regions were associated with HCPs' lower confidence in vaccine discussions and more perceiving these as burdensome, greater desire for training, and increased perceived responsibility for vaccination. Free-text responses described midwifery culture of providing vaccination information neutrally, avoiding direct recommendations in favour of supporting women's choice. ii) Mothers' survey: Most mothers (90%) rated HCPs as influential in their vaccination decision. Non-vaccination (20% of sample) was most strongly associated with lack of awareness that pertussis vaccination was recommended and lack of conviction that their midwife supported vaccination. Main reasons for vaccination were safety for the baby and HCP recommendation. Clear midwife recommendation was associated with satisfactory perceptions of vaccine communication across groups. The importance of access was commonly recognised but did not differentiate between groups in either study. Conclusions Midwives need support to avoid a neutral stance and provide clear, confident recommendations, including infant safety reassurance. Funding models should account for deprivation, not solely service size, to help reduce vaccination inequity.
BACKGROUND In the United States, adult vaccination coverage is low, contributing to high rates of vaccine-preventable diseases. State, local, and territorial health departments ('jurisdictions') use federal funding to support adult immunization programs, manage outbreaks, and provide vaccines to eligible adults. We identified five core adult immunization program components for a jurisdiction to be considered a robust program. We evaluated implementation of five core components of jurisdiction adult immunization programs and perceived success in providing vaccine access. METHODS We surveyed 64 CDC-funded jurisdictions on adult program operations and perceived success in vaccine access. RESULTS Variability in implementing core components was observed across jurisdictions, from 5% implementing none to 5% implementing all five and 90% implementing between one and four. Nineteen jurisdictions reported high perceived success in providing vaccine access. CONCLUSION This study highlights substantial variability in adult immunization program infrastructure and identifies funding diversification as a promising area to improve vaccine access.
Background The post-vaccination observation period ensures the rapid identification and clinical management of immediate adverse events following immunization, including anaphylaxis. Recommended observation periods vary internationally. In Canada, a 15 min observation period is standard. This systematic review assesses the empirical basis for these recommendations and the potential impact of varying observation period durations. Objective To describe time to onset of anaphylaxis following immunization and provide an empirical basis to evaluate variable post-vaccination observation period durations. Methods This study combined mixed methods to capture the available evidence base. A systematic review following PRISMA guidelines searched Embase and MEDLINE from inception to March 6, 2023, for studies reporting time to onset of anaphylaxis within 30 min of vaccination. Anaphylaxis reports submitted to the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS) were also analyzed. Results Of 44 studies reporting 1365 cases of anaphylaxis, 1229 (90%) had recorded onset time, of which 802 (65%) occurred within 30 min. Among cases with sufficient temporal detail (n = 305), 236 (77%) had onset within 15 min; of 113 cases with 5-min interval data, 61% had onset within 5 min. Findings were broadly consistent across COVID-19 and non-COVID-19 vaccines, age groups, and levels of diagnostic certainty. Among 2193 CAEFISS reports, the median onset time was 12 min; 78% (n = 1702) occurred within 30 min, 80% (n = 1363) of which occurred within 15 min, and 46% (n = 628) of those within 5 min. Results were similar across age groups and vaccine types. Conclusions Vaccine-associated anaphylaxis most commonly presents within 15 min of vaccination. A routine 15-min observation period would be expected to capture most (77–80%) events occurring within 30 min.
Purpose of research Long COVID (LC) risk varies across SARS-CoV-2 variants, but causal inference is complicated by rising vaccine coverage coinciding with viral evolution. We examined how pre-infection vaccination status modified LC risk across different pandemic periods dominated by different variants, to disentangle the contributions of viral evolution and vaccine-induced immunity.In this prospective cohort study of Israeli adults with SARS-CoV-2 infections from July 2021–March 2023, participants completed baseline and follow-up online surveys ≥60 days post-infection. LC was defined as ≥3 symptoms within validated symptom clusters. Infections were assigned to an infection period corresponding to the predominant circulating variant (Wild type, Alpha, Delta, Omicron) at onset time. Pre-infection vaccination was categorized as unvaccinated (0–1 doses), partially vaccinated (2 doses), or fully vaccinated (≥3 doses). Generalized estimating equations estimated multivariable risk ratios, adjusted for age, sex, and follow-up time. Among 1715 participants reporting 2018 infections, LC was reported following 30·4% of infections. In models adjusted for vaccination, LC risk did not differ between the Delta and Omicron-dominant periods (aRR 1·01, 95% CI 0·80–1·26). Among partially vaccinated individuals, infections during the Omicron-dominant period carried lower LC risk than during Delta (aRR 0·62, 95% CI 0·40–0·98). LC risk did not differ by variant-dominant periods among unvaccinated or fully vaccinated individuals. Major conclusions Observed differences in LC risk at various periods of the pandemic dominated by different variants may be largely explained by concurrent increases in vaccine coverage rather than intrinsic changes in variant pathogenicity. Full pre-infection vaccination conferred consistent protection against LC regardless of the period of variant dominance.
