Comparative Cost-Effectiveness Analysis of Respiratory Syncytial Virus Vaccines for Older Adults in Hong Kong.

Two respiratory syncytial virus (RSV) vaccines (AREXVY and ABRYSVO) were recently approved for older adults in the US. This study aimed to evaluate the cost-effectiveness of AREXVY and ABRYSVO from the Hong Kong public healthcare provider's perspective. A two-year decision-analytical model was developed to examine the outcomes of a single RSV vaccination (AREXVY or ABRYSVO) compared to no vaccination. Primary outcomes included RSV-related health outcomes, direct medical costs, quality-adjusted life-year (QALY) loss, and incremental cost per QALY (ICER). RSV vaccines are not yet marketed in Hong Kong, base-case analysis, therefore, benchmarked US RSV vaccine prices at 4 levels (25%, 50%, 75%, 100%). AREXVY and ABRYSVO (versus no vaccination) gained 0.000568 QALY and 0.000647 QALY, respectively. ICERs of ABRYSVO (26,209 USD/QALY) and AREXVY (47,485 USD/QALY) were lower than the willingness-to-pay threshold (49,594 USD/QALY) at 25% US vaccine price. The RSV attack rate was a common influential factor at all vaccine price levels. The probabilities of AREXVY and ABRYSVO to be most cost-effective were 0.10% and 97.68%, respectively, at 25% US vaccine price. Single vaccination of ABRYSVO or AREXVY for older adults appears to gain QALYs over 2 years in Hong Kong. The cost-effectiveness of AREXVY and ABRYSVO is subject to vaccine price and RSV attack rate.