Cost-effectiveness of immunising interventions to reduce respiratory syncytial virus disease burden in infants in Australia

Abstract Background Two immunising products are emerging to prevent the burden of respiratory syncytial virus (RSV) in infants: long-lasting monoclonal antibodies (mAbs) and maternal vaccines given during pregnancy (MV). This study assesses the potential cost-effectiveness of programs involving each product, to help inform policy decisions related to their implementation in the Australian context. Methods We developed an individual-based dynamic transmission model of RSV infection, linked to a clinical pathways model and cost-effectiveness model. We modelled key scenarios exploring varying eligibility and coverage of immunisation products for at-risk and not-at-risk populations, in addition to sensitivity analyses of immunisation characteristics, program costs, and the impact of potential under-ascertainment of RSV burden. We estimated the cost-effectiveness of each program from a health system perspective, with results presented as incremental cost-effectiveness ratios in terms of cost per quality-adjusted life year gained (QALY). Findings We found a combined program in which administration of MV during pregnancy is supplemented with a birth-dose of mAbs for newborns born without protection from MV is likely to be cost-saving, compared to the status quo of no MV or mAbs delivered. This program averted on average 41% of infant hospitalisations per year and reduced QALY losses by 33%. Interpretation Programs combining infant immunisation products are likely to significantly reduce the burden of RSV disease in Australia, and be cost-saving. However, their estimated impact and cost-effectiveness is strongly dependent on key assumptions i) the consistency and completeness of ascertainment of disease burden over time; ii) the cost of a hospitalisation and immunising dose; iii) the efficacy and durability of protection of the modelled products, and; iv) the timing and coverage of the immunisation delivery. Funding This modelling was commissioned by the National Immunisation Division of the Australian Government Department of Health, Disability and Ageing.