Health literacy in relation to vaccine hesitancy: Systematic review of observational studies

Abstract Background Vaccine hesitancy is considered by the WHO as one of the major global public health threats. Identifying modifiable predictors of vaccine hesitancy is instrumental for attempts aimed at tackling this alarming phenomenon. By carrying out a systematic review, we aimed to investigate the presence and nature of the association between health literacy and vaccine hesitancy. Methods We carried out a systematic search of the literature in PubMed and Scopus, applying specific study inclusion criteria to identify studies that investigated the association of interest based on validated assessment tools. Relevant publications were screened for eligibility, while quality was independently assessed by two researchers based on the Newcastle-Ottawa scale. Results We identified 17 relevant studies (16 cross-sectional and 1 case-control). Sample size ranged from 230 to 3360, while studies involved childhood as well as adult (e.g. flu, COVID-19) vaccines. All included studies assessed health literacy and vaccine hesitancy as composite scales, with the majority using comprehensive validated scales. The majority of studies, but not all, adjusted for potential confounders. The vast majority (16/17) of studies reveal a negative association, with individuals scoring high on health literacy, scoring low on vaccine hesitancy. An exception was identified where higher health literacy was associated with higher vaccine hesitancy among parents as regards childhood vaccinations. Conclusions Our systematic review provides strong evidence suggesting that higher health literacy is linked to lower vaccine hesitancy. This inverse association might not be apparent in all contexts however, as cultural factors and the nature of vaccination, might reverse this relationship. Public Health approaches aimed at tackling vaccine hesitancy and reducing the burden from emerging and re-emerging infectious diseases, should focus on increasing health literacy, among other factors. Key messages • Overwhelming evidence suggests that higher health literacy is linked to lower vaccine hesitancy in the majority of contexts. • Increasing health literacy is a promising target for tackling vaccine hesitancy and its detrimental consequences in the fight against the control of emerging and re-emerging infectious disease.