Author:
Shi Xiangyu (Chianti),Gruber Joann F.,Ondari Michelle,Lloyd Patricia C.,Duenas Pablo Freyria,Clarke Tainya C.,Nadimpalli Gita,Cho Sylvia,Feinberg Laurie,Hu Mao,Chillarige Yoganand,Kelman Jeffrey A.,Forshee Richard A.,Anderson Steven A.,Shoaibi Azadeh
Abstract
AbstractBackgroundWhile 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.MethodsA 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, seasonality, and outcome misclassification. For AEs with any statistically significant associations, we stratified results by concomitant vaccination status.ResultsAmong 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 those with and without concomitant vaccination, respectively.ConclusionsRates 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.
Publisher
Cold Spring Harbor Laboratory
Reference37 articles.
1. Centers for Disease Control and Prevention. Seasonal Flu Vaccines 2023 [Available from: https://www.cdc.gov/flu/prevent/flushot.htm#:~:text=For%20the%202022%2D2023%20flu%20season%2C%20there%20are%20three%20flu,Fluad%20Quadrivalent%20adjuvanted%20flu%20vaccine.
2. High Clinical Burden of Influenza Disease in Adults Aged ≥ 65 Years: Can We Do Better? A Systematic Literature Review;Advances in therapy,2023
3. Centers for Disease Control and Prevention. Weekly Flu Vaccination Dashboard [cited 2023. Available from: https://www.cdc.gov/flu/fluvaxview/dashboard/vaccination-dashboard.html.
4. Centers for Disease Control and Prevention. What Vaccines are Recommended for You [cited 2023. Available from: https://www.cdc.gov/vaccines/adults/rec-vac/index.html.
5. Encephalitis after influenza and vaccination: a nationwide population-based registry study from Norway;International Journal of Epidemiology,2017