Economic evaluation of hepatitis A vaccines by income level of the country: A systematic review.

Background & objectives: Although several reviews of economic evaluation (EE) studies on hepatitis A virus (HAV) vaccine exist, there remains a need to corroborate such data from time to time. This study aimed to systematically review the literature for reports on EE of HAV vaccination by type of population, characteristics of intervention and income level of the country. Methods: PubMed and Scopus were searched to identify relevant studies from inception up to May 2021 using topic-specific key words in various combinaiton. Full EE studies comparing HAV vaccination to no vaccine or immunoglobulin were included. The risk of bias was assessed by using the ECOBIAS checklist. Results: Among the 1984 identified studies, 43 were found eligible. Of these, 27 were from high-income countries (HICs), 15 from middle-income countries (MICs), and one from low income country. Majority of the studies used Markov model and/or decision tree (n=26). Eight studies used a dynamic model. The discount rate, perspective and time horizon varied across the studies. Universal HAV vaccination without screening was cost-effective among children (14/16, 87.5%) and adolescents (1/5, 20%) but not in adults (0/4, 0%). Analysis by the level of income found that universal HAV vaccination among children without screening was cost-effective in 81.8 per cent of the studies conducted in MICs (9/11) as compared to 66.7 per cent in HICs (4/6). About one-third of the studies conducted among children found that screening and HAV vaccination were cost-effective compared to no vaccination. Interpretation & conclusions: The finding of this review suggest that universal vaccination of children without screening was likely to be cost-effective, especially in MICs. Nevertheless, it should be noted that the methodology varied across studies. Several aspects should also be considered in transferring the EE results across jurisdictions.