Factors associated with the uptake of seasonal influenza vaccination in adults: a systematic review

Studies on different populations have shown that a variety of factors influence attitudes and decision in the general population on vaccine uptake. This study explores factors associated with the uptake of influenza vaccination among adults. A systematic literature review was performed on literature searched in databases EMBASE, MEDLINE, Cochrane Library and Electronic Theses Online Service up until November 2013. A critical appraisal framework was designed to assess the methodological quality of the studies. Twenty-three articles met the inclusion criteria and were selected for outcome analysis and 21 were quantitative observational studies. Advancement in age (OR 1.06–23.7) and having chronic diseases (OR 1.38–13.7) were strongly indicative of vaccine uptake. Perceptions on vaccine efficacy (OR 2.7–10.55) and vaccine safety and adverse events (OR 10.5) were more influential than the level of knowledge on influenza and its vaccination. Advice from doctors/health professionals/family and/or close friends and free vaccination were also key factors in association with uptake of vaccination. This review highlighted the finding that perception on vaccine efficacy, perception on vaccine safety and adverse events, advice from doctors/health professionals/family/close friends and free vaccination are changeable factors that are strongly associated with influenza vaccination in adults aged 18–64.