Adverse events affecting recovery from seasonal influenza vaccination in the hypertensive population: A population-based pharmacovigilance analysis

Seasonal influenza vaccination is crucial for preventing influenza and its complications. Data from the United States Vaccine Adverse Event Reporting System (VAERS) indicate a higher proportion of adverse events (AEs) after influenza vaccination in hypertensive people. However, there is limited evidence on AEs in hypertensive people following seasonal influenza vaccination. We identified 4647 individuals aged 18 years or older with a history of hypertension who received seasonal influenza vaccination and 6380 seasonal influenza-vaccine-induced AEs between 1 January 2013 and 23 June 2023 from VAERS. We identified two groups for comparison: recovery and no recovery from seasonal influenza-vaccine-induced AEs. Propensity score matching (PSM) was performed to adjust for potential confounding factors, including demographic characteristics (age, sex, and region) and season of onset. Cox regression analysis was used to calculate the risk ratio of reported adverse events (AEs) that affected recovery after seasonal influenza vaccination. Most AEs were nonserious and occurred within 48 hours. The most common AEs were general disorders and administration site conditions (therapeutic and non-therapeutic responses, inflammation) and musculoskeletal and connective tissue disorders (musculoskeletal and connective tissue pain and discomfort, bursal disorders, joint-related signs, and symptoms). All three types of seasonal influenza vaccines were associated with injection site reactions (47.07% trivalent influenza vaccine [TIA], hazard ratio, HR 2.04, 95% confidence interval, CI 1.22-3.40; 20.00% quadrivalent influenza vaccine [QIA], HR 2.81, 95% CI, 1.81-4.37; 67.48% influenza vaccine, unknown manufacturer [FLUX], HR 2.83, 95% CI, 1.12-7.15) and were the AEs affecting the largest proportion of delayed recoveries in the hypertensive population. Potential AEs following seasonal influenza vaccination may affect the recovery of the hypertensive population. The majority of AEs reported were general disorders, predominantly injection site reactions, and nonserious.