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) from health care payer's perspective: no universal immunisation, year-round or seasonal maternal vaccination (MV), year-round or seasonal nirsevimab (NmAb) at birth, seasonal NmAb+catch-up for infants ≤ 6-month and a combined MV+NmAb with catch-up strategy. Seasonal NmAb+catch-up averted the most disease, while seasonal MV averted the least, but had the lowest incremental cost-effectiveness ratio (€11,276/QALY gained) 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 a willingness to pay of €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 preferred at low MV and NmAb costs. Besides price level, cost-effectiveness was most sensitive to RSV hospital burden.