Assessment of potential adverse events following the 2022-2023 seasonal influenza vaccines among U.S. adults aged 65 years and older.

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.

Detection of SARS-CoV-2-specific mucosal antibodies in saliva following concomitant COVID-19 and influenza vaccination in the ComFluCOV trial.

The ComFluCOV trial randomized 679 participants to receive an age-appropriate influenza vaccine, or placebo, alongside their second COVID-19 vaccine. Concomitant administration was shown to be safe, and to preserve systemic immune responses to both vaccines. Here we report on a secondary outcome of the trial investigating SARS-CoV-2-specific mucosal antibody responses. Anti-spike IgG and IgA levels in saliva were measured with in-house ELISAs. Concomitant administration of an influenza vaccine did not affect salivary anti-spike IgG positivity rates to Pfizer/BioNTech BNT162b2 (99.1 cf. 95.6%), or AstraZeneca ChAdOx1 (67.8% cf. 64.9%), at 3-weeks post-vaccination relative to placebo. Furthermore, saliva IgG positively correlated with serum titres highlighting the potential utility of saliva for assessing differences in immunogenicity in future vaccine studies. Mucosal IgA was not detected in response to either COVID-19 vaccine, reinforcing the need for novel vaccines capable of inducing sterilising immunity or otherwise reducing transmission. The trial is registered as ISRCTN 14391248.

Herpes Zoster Following Recombinant Zoster Vaccine With or Without Concomitant Vaccination.

BACKGROUND: The 2-dose recombinant zoster vaccine (RZV) series is recommended for prevention of herpes zoster (HZ) in adults aged ≥50 years, but data are limited on the impact of concomitant administration with other vaccines on subsequent HZ risk. METHODS: This cohort study included Kaiser Permanente Southern California members aged ≥50 years who received 2 doses of RZV 4 weeks to ≤6 months apart during 1 April 2018-30 September 2019. RZV recipients with and without same-day concomitant vaccination for either RZV dose were followed up for incident HZ beginning 31 days after the second RZV dose until 30 September 2020. The hazard ratio (HR) for HZ comparing RZV recipients with and without concomitant vaccination was estimated using Cox proportional hazards regression, adjusting for confounders. RESULTS: RZV with and without concomitant vaccination was received by 12 898 and 28 353 individuals, respectively. HZ occurred among 41 individuals with concomitant vaccination (incidence rate, 2.2 [95% confidence interval {CI}, 1.6-3.0] per 1000 person-years) and 136 without concomitant vaccination (3.4 [95% CI, 2.9-4.0] per 1000 person-years). The adjusted HR for HZ comparing RZV recipients with and without concomitant vaccination was 0.75 (95% CI, .53-1.08). CONCLUSIONS: HZ risk was not significantly different between RZV recipients with and without concomitant vaccination, supporting recommendations allowing for concomitant administration of RZV with other vaccines.

Concomitant HPV and MenACWY vaccination among sixth and seventh graders receiving Tdap.

OBJECTIVE: To describe use of human papilloma virus (HPV) and meningococcal (MenACWY) vaccines among sixth and seventh grade Kansas children receiving their school-required tetanus, diphtheria, and acellular pertussis (Tdap) booster. METHODS: We used Medicaid and commercial claims data in Kansas from 2013, 2014, and 2015 to identify HPV and MenACWY vaccinations among sixth and seventh graders receiving a Tdap booster. Rates of concomitant vaccinations were calculated at the state and county level, and logistic regression was used to identify predictors of concomitant vaccination. RESULTS: Of sixth and seventh graders in Kansas receiving their required Tdap booster, 53-82% failed to receive a concomitant HPV vaccine and 36-47% failed to receive a concomitant MenACWY vaccine from 2013 to 2015. Rates of concomitant vaccinations varied more than four-fold across counties. Female gender, younger age, and Medicaid (versus commercial insurance) were positively associated with concomitant vaccination; concomitant vaccination rates increased from 2013 to 2015 (p < 0.001). Of children continuously enrolled in Medicaid from 2013 to 2015, who did not receive concomitant vaccination in 2013, 72.3% and 68.6% remained unvaccinated against HPV and MenACWY, respectively by the end of 2015. CONCLUSIONS: Failure to get a concomitant vaccination at the time of their Tdap booster identifies children at high risk of not getting immunized in the ensuing 2-3 years. 'Back to school' programs focusing only on school-required vaccinations could have negative impacts on overall vaccination rates. Tracking rates of concomitant vaccination might be useful in supporting quality assessment and improvement efforts. CLINICAL TRIAL REGISTRATION: This study was not a clinical trial.

Utilization pattern of Haemophilus influenza type b vaccine in eight provinces of China.

OBJECTIVE: In China, Hib vaccine is a private-sector vaccine that is an option for parents to select to give to their children; it must be paid for out-of-pocket because it is not included in the government's Expanded Program on Immunization (EPI). We evaluated utilization patterns of Hib vaccine to provide evidence in support of development of a national Hib vaccination strategy. METHODS: We obtained lists of children from immunization information systems (IIS) of counties or districts in 8 provinces of China. Using these lists, we selected 10 children at random from each birth cohort from 2008 through 2012. We obtained Hib vaccination dates from official vaccination certificates. The target sample size was 1,000 children. RESULTS: We were able to obtain records for 978 subjects of the selected subjects; of these, 44.79% had received at least 1 dose of Hib vaccine, and 15.54%, 5.83%, 12.27%, and 11.15% had received one, two, three, and four doses, respectively. Per capita GDP was positively correlated with receipt of at least one dose of Hib vaccine. Among the 438 subjects who received Hib vaccine, 27% received 1 dose after 12 months of age; 15%, 7%, and 23% received one of three other patterns of Hib vaccination recommended by the World Health Organization (WHO) [a 3-dose primary series; 2 primary series doses and 1 booster; or 3 primary series doses and 1 booster]. The other 28% of subjects received patterns of Hib vaccination not recommended by WHO. Considering protection from Hib disease as receipt of a WHO-recommended Hib vaccine schedule, 29% of subjects could be considered protected after 12 months of age, 52% could be considered protected during infancy and beyond, and 19% could be considered to not have been protected adequately, despite being vaccinated. CONCLUSIONS: Coverage with Hib vaccine was low. There were significant differences between WHO recommendations and actual patterns of use of Hib vaccine, with half of vaccine recipients receiving no protection during infancy and one fifth receiving non-protective Hib vaccination patterns. Inclusion of Hib vaccine into China's EPI system, which provides vaccine at no charge to parents and makes specific vaccination schedule standards, has potential to make more effective use of Hib vaccine.

One-year immunogenicity kinetics and safety of a purified chick embryo cell rabies vaccine and an inactivated Vero cell-derived Japanese encephalitis vaccine administered concomitantly according to a new, 1-week, accelerated primary series.

BACKGROUND: Conventional rabies pre-exposure prophylaxis (PrEP) and Japanese encephalitis (JE) primary series vaccination regimens each require up to 4 weeks to complete and, thus, may not be feasible for individuals who need these immunizations on short notice. This Phase 3b, randomized, controlled, observer-blind study evaluated the immunogenicity and safety of concomitant administration of a purified chick embryo cell culture rabies vaccine and an inactivated, adsorbed JE vaccine according to an accelerated (1 week) regimen when compared with the conventional regimens (4 weeks). This report describes the kinetics of immune responses up to 1 year after vaccination. METHODS: A total of 661 healthy adults (18 to ≤65 years) were randomized into the following accelerated or conventional vaccine regimens: Rabies + JE-Conventional, Rabies + JE-Accelerated, Rabies-Conventional and JE-Conventional. Immunogenicity was assessed by virus neutralization tests. Safety and tolerability were also evaluated. RESULTS: Irrespective of rabies vaccination regimen, ≥97% of subjects had adequate levels of rabies virus neutralizing antibody (RVNA) concentrations (≥0.5 IU/ml) up to Day 57, with percentages of subjects with RVNA concentrations ≥0.5 IU/ml at Day 366 ranging between 68% in the Rabies + JE-Accelerated group and 80% of subjects in the Rabies-Conventional group. The Rabies + JE-Accelerated group revealed high JE neutralizing antibody titers at all-time points. At Day 366, the percentage of subjects with antibody titers indicative of seroprotection (PRNT50 titers ≥1:10) remained high across JE vaccine groups (86-94%). CONCLUSIONS: The accelerated PrEP rabies and JE vaccination regimens, once licensed, could represent a valid alternative in the short-term to currently recommended conventional regimens. The concomitant administration of these two vaccines does not compromise immune responses to any of the vaccine antigens particularly when aiming for short-term protection. Further evidence will clarify the need for and timing to administration of rabies vaccine booster doses in subjects primed with an accelerated PrEP regimen. (NCT01662440).