Adverse Reactions and Vaccination Preferences Following COVID-19 and Influenza Vaccination Among Healthcare Workers:...

Co-administration of COVID-19 and influenza vaccines has been promoted to improve coverage, but acceptance among healthcare workers (HCWs) remains uncertain. In total, 1238 participants were recruited. Participants were categorized by vaccination pattern including same-day co-administration, non-concurrent vaccination, or single vaccine. Linear regression and multinomial logistic regression were used to assess adverse reactions, association with prior COVID-19 vaccination experiences and future vaccination preferences. HCWs who received same-day co-administration reported higher adverse reaction scores (1.10 ± 0.92) and prevalence (72.5%) compared to non-concurrent vaccination (0.88 ± 0.84, 63.0%) or single vaccine recipients (0.68 ± 0.80, 31%-48%). Prior adverse reactions positively correlated with 2024 reactions (r = 0.30-0.49, p < 0.0001). Non-concurrent vaccination (β = -0.26) and single vaccine receipt (β = -0.45) were associated with lower adverse reaction scores than same-day co-administration. Among non-concurrent vaccination recipients, flu-first vaccination was associated with lower adverse reaction scores than COVID-first (β = 0.30). Past vaccination patterns showed significant association with future choices. In this study, HCWs who received same-day co-administration of COVID-19 and influenza vaccines reported higher adverse reaction scores compared to those who received non-concurrent or single vaccines. These findings suggest that vaccination scheduling preferences warrant consideration in institutional immunization programs. Prospective research is needed to confirm these associations and determine appropriate vaccination strategies.