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

Background: 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. Methods: 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. Results: 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. Conclusions: 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.