Health behaviors are largely not predictive of adverse events following influenza vaccination

Identifying health behaviors associated with adverse events following immunization (AEFI) could identify intervention targets for AEFI prevention. University employees receiving an influenza vaccination (n = 1301) completed a series of online surveys for health behaviors including sleep, exercise, dietary intake, and smoking habits, and emotional state (baseline), and for indications of AEFI (three days post-vaccination) and influenza-like illness (ILI) symptoms (fortnightly follow-up for 4 months). 29.9% of participants reported an AEFI and 46.0% reported experiencing ILI during follow-up. Multivariate logistic regression revealed usual sleep duration was associated with AEFI (odds ratio 1.20, 95% confidence interval 1.03–1.41), increasing with each hour of sleep. ILI was associated with reporting AEFI (1.70, 1.24–2.33), increasing BMI (1.03, 1.00–1.06) and survey response frequency (1.13, 1.04–1.22), and decreased with better usual sleep quality (0.96, 0.92–1.00) and with increasing age (0.98, 0.96–1.00). Sex stratification revealed no significant predictors of AEFI for either sex; in women, experiencing AEFI increased likelihood of ILI (1.88, 1.25–2.85) and in men, survey completion frequency increased ILI likelihood (1.19, 1.05–1.36). Our study suggests modifying health behaviors would not alter AEFI risk and reactogenicity may signal weaker immunogenicity but confirmation through objective measures is warranted.