Bidirectional associations between influenza and COVID-19 vaccination: a systematic review and meta-analysis

Purpose: This study aimed to investigate the effect of vaccination history on future willingness or behavior to receive vaccinations for influenza and COVID-19. Methods: In this systematic review and meta-analysis, the PubMed, Embase, Web of Science, Cochrane Library, APA PsycInfo, CINAHL and Scopus databases were searched up to February 28, 2026, to identify relevant studies in accordance with the inclusion and exclusion criteria. The analysis ultimately included 145 population-based studies conducted in the United States, China, Thailand, the United Arab Emirates, Egypt, and other countries. Results: Prior vaccination histories for influenza and COVID-19 interacted with each other and were associated with an increased willingness and likelihood to receive future vaccines. Specifically, having received the influenza vaccine was associated with an increased willingness to receive the COVID-19 vaccine(odds ratio [OR] = 2.73, 95% confidence interval [CI]: 2.34-3.19, 95% prediction interval:[PI] 0.66-11.07), as well as with an increased likelihood of actually receiving the COVID-19 vaccine (OR = 2.76, 95% CI: 2.32-3.29, 95%PI: 0.90-8.52). Receiving a COVID-19 vaccine was associated with an increased willingness to receive a influenza vaccine (OR = 3.04, 95% CI: 1.25-7.39), and was also associated with an increased likelihood of actually receiving the influenza vaccine (OR = 3.91, 95% CI: 2.45-6.24, 95%PI: 0.81-18.81). Conclusion: In conclusion, prior vaccination history was associated with higher odds of future vaccination, and influenza and COVID-19 vaccination experiences influenced each other. Influenza and COVID-19 vaccine promotion strategies can likely be combined to increase overall vaccination rates. Systematic review registration: PROSPERO identifier CRD42024594174.