Estimating the cost-effectiveness of maternal vaccination and monoclonal antibodies for respiratory syncytial virus in Kenya and South Africa

Abstract

AbstractBackgroundRespiratory syncytial virus (RSV) causes a substantial burden of acute lower respiratory infection in children under 5 years, particularly in low- and middle-income countries (LMICs). Maternal vaccine (MV) and next-generation monoclonal antibody (mAb) candidates have been shown to reduce RSV disease in infants in phase III clinical trials. The cost-effectiveness of these biologics has been estimated using disease burden data from global meta-analyses, but these are sensitive to the detailed age breakdown of paediatric RSV disease, for which there have previously been limited data.MethodsWe use original hospital-based incidence data from South Africa and Kenya collected between 2010 and 2018 of RSV-associated acute respiratory infection (ARI), influenza-like illness (ILI), severe acute respiratory infection (SARI) as well as deaths with monthly age-stratification, supplemented with data on healthcare-seeking behaviour and costs to the healthcare system and households. We estimated the incremental cost per DALY averted (incremental cost-effectiveness ratio or ICER) of public health interventions by MV or mAb for a plausible range of prices (3-30 USD for vaccines and 6-60 USD for monoclonals), using an adapted version of a previously published health economic model (McMarcel) of RSV immunisation.ResultsOur data show higher disease incidence for infants younger than 6 months of age in the case of Kenya and South Africa than suggested by earlier projections from community incidence-based meta-analyses of LMIC data. Since MV and mAb provide protection for these youngest age groups, this leads to a substantially larger reduction of disease burden and therefore, more favourable cost-effectiveness of both interventions in both countries. Specifically, using published efficacy data, our mean estimate for reducing RSV-associated deaths in children under 5 years of age is 9% for MV and 28% for mAb in Kenya. In South Africa, the reduction is larger, with the mean estimate of 14% for MV and 48% for mAb.In the case of the lowest dose prices (3 USD for MV and 6 USD for mAb), the healthcare system perspective ICERs per DALY averted drop to 144 USD (mAb) and 397 USD (MV) in Kenya, whereas it is net cost-saving from the perspective of the South African healthcare system. At the highest assumed dose prices of 30 USD for MV and 60 USD for mAb, the median estimates for the ICER are 4528 USD for MV and 2748 USD for mAb in Kenya, while in South Africa, it is 4694 USD for MV and 2566 USD for mAb.ConclusionInterventions against RSV disease may be more cost-effective than previously estimated following the incorporation of new data indicating that the disease burden is highly concentrated in the first 6 months of life in two African settings.