OBJECTIVES: To provide an up-to-date evaluation of the cost-effectiveness of palivizumab versus no prophylaxis in moderate-to-late preterm (32-35 weeks’ gestational age [wGA]) infants.

METHODS: A systematic review of previous economic evaluations of palivizumab in 32-35wGA infants (20 studies from 7 countries identified) and expert input informed the development of a new cost-utility model. Infants received palivizumab if scored at moderate-or-high risk of RSV hospitalisation (RSVH) using the International Risk Scoring Tool (IRST) and entered a semi-Markov process resulting in: i) RSVH; ii) emergency room/outpatient-attended RSV illness; or iii) uninfected/non-medically attended RSV illness. RSVH rates for prophylaxed vs unprophylaxed moderate-or-high risk infants were 1.8% and 6.3%, respectively. Mortality (0.43%) was applied only in intensive care and long-term respiratory morbidity modelled to 18 years across a lifetime horizon. Direct and indirect costs were included (1.5% discounting) based on the Canadian healthcare perspective. No vial sharing was permitted in the base case (50mg: CAN$752; 100mg: $1,505).

RESULTS: Palivizumab was highly cost-effective with a cost per quality-adjusted life year (QALY) of CAN$18,545 versus no prophylaxis in moderate-or-high risk infants (Canadian threshold typically stated as $50,000). For high- and moderate-risk infants alone, results were $14,570/QALY and $23,109/QALY, respectively. Deterministic sensitivity analyses (±20% on main variables) revealed the model was most sensitive to utility scores, palivizumab cost, non-prophylaxed RSV hospitalisation rate, and long-term respiratory morbidity rate. Probabilistic sensitivity analyses (10,000 iterations) resulted in a mean $19,376/QALY, with a 92.4% probability of palivizumab being cost-effective at a $50,000 willingness-to-pay threshold and 97.6% probability at $75,000. Vial sharing (5% wastage) considerably improved cost-effectiveness ($12,552/QALY), while no discounting ($15,864/QALY) and excluding indirect costs ($18,133/QALY) had more limited impact.

CONCLUSIONS: This new economic analysis demonstrated palivizumab to be highly cost-effective versus no prophylaxis in moderate-or-high risk 32-35wGA infants in the Canadian healthcare context.