Impact and cost-effectiveness of maternal vaccine and short and long-acting monoclonal antibodies against respiratory syncytial virus among children in Japan: A modeling study

Respiratory syncytial virus (RSV) infection is one of the most common causes of lower respiratory infection globally. Three prevention measures—short-acting monoclonal antibody (sa-mAb) and long-acting monoclonal antibody (la-mAb) for infants, and RSV prefusion F protein vaccine maternal vaccine (MV) for pregnant women—are approved for use in Japan. We aim to evaluate the cost-effectiveness of multiple interventions to lower RSV disease burden among under-2-year-old children in Japan. We assessed the cost-effectiveness of six strategies for preventing RSV infection in comparison to no immunization; (i) sa-mAb for high-risk infants, (ii) MV for all pregnant women, (iii) la-mAb for high-risk infants, (iv) la-mAb seasonal administration to all infants who were born between September and March, (v) la-mAb seasonal administration with catch-up administration in September for infants who were born between April and August, and (vi) la-mAb year-round administration to all infants. We also assessed the cost-effectiveness of MV combined with mAb for high-risk infants in comparison to-only MV. We conducted threshold analyses to identify the maximum price of MV and la-mAb at which they are cost-effective. We estimated the incremental cost-effectiveness ratio (ICER) for the maternal vaccine at JPY 6.7 million per quality-adjusted life year (QALY) gained, which exceeded the willingness-to-pay threshold in Japan of JPY 5 million per QALY gained. For la-mAb, the most cost-effective strategy was seasonal administration, although the ICER was over 180 million JPY per QALY gained with the current market price. A combination strategy of MV and mAb for high-risk infants was not cost-effective regardless of the prices of mAb. We estimated the threshold prices of MV at JPY 17,251 and la-mAb at JPY 11,443–14,143. Among the RSV preventive interventions, MV was closest to being cost-effective. However, the price would have to be lowered for it to be cost-effective in Japan. • Short-, and long-acting monoclonal antibody, and maternal vaccine reduce RSV burden in Japan. • Maternal vaccine was closer to being cost-effective in preventing RSV in Japan. • Maternal vaccine with long-acting mAb for high-risk infants was not cost-effective in Japan.