Cost-effectiveness of maternal vaccine and/or monoclonal antibody strategies against respiratory syncytial virus in Belgian infants

The respiratory syncytial virus (RSV) burden and cost-effectiveness of infant RSV immunisation was evaluated by comparing seven strategies in terms of costs and Quality-Adjusted Life Years (QALYs): no universal immunisation, year-round or seasonal maternal vaccination (MV), year-round or seasonal nirsevimab (NmAb) at birth, seasonal NmAb plus a catch-up for infants≤6-month and a combined MV+NmAb strategy. Seasonal NmAb with catch-up was most effective, while seasonal MV was least effective, but most cost-effective for healthcare at current list prices (MV €186, NmAb €778). Extensive trade-offs between NmAb and MV show at which cost per dose which strategy would be deemed cost-effective. At willingness-to-pay €35,000/QALY gained, seasonal NmAb+catch-up was preferred if NmAb<€210; otherwise, seasonal or year-round MV was preferred when MV < €220 or < €75, respectively. The combined strategy became optimal at low MV and NmAb cost levels. Besides price level, cost-effectiveness was most sensitive to RSV hospital burden.