Evidence-to-policy gap on hepatitis A vaccine adoption in 6 countries: Literature vs. policymakers' beliefs

Background: National vaccine adoption decisions may be better understood by linking multiple data sources. When examining countries' decisions to adopt the hepatitis A vaccine, applying multiple research methods can facilitate assessments of gaps between evidence and policy. We conducted a literature review on hepatitis A and stakeholder interviews about decisions to adopt the vaccine in six countries (Chile, India, South Korea, Mexico, Russia, and Taiwan). Methods: A systematic literature review was conducted across five literature databases. The review identified and abstracted 340 articles, supplemented by internet search. In addition, we interviewed 62 experts and opinion leaders on hepatitis A and/or vaccines. Data from the two sources were analyzed to identify gaps around epidemiologic data, economic data, and barriers/facilitators of hepatitis A vaccine adoption. Results: Epidemiologic data gaps were found in Chile and Russia, where stakeholders believed data to be more solid than the literature documented. Economic data on hepatitis A was found to be weak across all countries despite stakeholders' agreement on its importance. Barriers and facilitators of vaccine adoption such as political will, prioritization among vaccines, and global or local recommendations were discussed more by stakeholders than the literature. Stakeholders in India and Mexico were not concerned with the lack of data, despite growing recognition in the literature of the epidemiological transition and threat of outbreaks. Conclusions: Triangulation of results from two methods captured a richer story behind vaccine adoption decisions for hepatitis A. The discrepancy between policymakers' beliefs and existing data suggest a decline in priority of hepatitis A or weak investment in data collection. Filling the confirmed data gaps in seroprevalence or economic data is important to help guide policy decisions. Greater communication of the risk of hepatitis A and the benefits of the vaccine may help countries undergoing the epidemiologic transition.