Abstract
A number of cost-effectiveness analysis of influenza vaccination have been conducted to estimate value of influenza vaccines in elderly and health workers (HWs). This study aims to summarize cost-effectiveness evidence by pooling the incremental net monetary benefit (INB) of influenza vaccination. A systematic review was performed in electronic databases from their inceptions to February 2022. Cost-effectiveness studies reporting disability-adjusted life-years (DALY), quality-adjusted life year (QALY), or life year (LY) of influenza vaccination were included. Stratified meta-analyses by population, perspective, country income-level, and herd-effect were performed to pool INB across studies. 21 and 15 studies were included in the systematic review and meta-analysis respectively. All included studies in the meta-analysis were conducted in elderly. According to pre-specified analyses, studies for elderly in high-income economies (HIEs) and upper-middle income economies (UMIEs) without herd effect could be pooled. For HIEs under a societal perspective, the perspective which identify all relevant costs occurred in the society including direct medical cost, direct non-medical cost and indirect cost, pooled INB was $217.38 (206.23, 228.53, I2 =28.2%), while that for healthcare provider/payer perspective was $0.20 (-11,908.67, 11,909.07, I2 = 0.0%). For societal perspective in UMIEs, pooled INB was $28.39 (-190.65, 133.87, I2 = 92.8%). The findings were robust across a series of sensitivity analyses for HIEs. Studies in HWs indicated that influenza vaccination was cost-effective compared to no vaccination or current practice. Influenza vaccination might be cost-effective for HWs and elderly in HIEs under a societal perspective with relatively small variations among included studies, while there remains limited evidence for healthcare provider/ payer perspective or other level of incomes. Further evidence is warranted.