Routine childhood rabies pre-exposure prophylaxis can be cost effective in low- and middle-income countries.

Abstract

Background: Pre-exposure prophylactic rabies vaccination (PrEP) is advised for travellers to countries with high rabies incidence, but rarely available for local residents. Some studies suggest poor cost-effectiveness of PrEP in such settings, but have generally focused upon post-exposure prophylaxis (PEP) cost savings as the main benefit of PrEP, without considering lives saved by PrEP efficacy.

Methods: We compared incremental cost-effectiveness ratios (ICERs) of use of rabies PrEP, against an alternative of using only PEP, by adapting a decision-tree model previously used to inform Gavi's investment in rabies PEP. We consider scenarios including: a range of PrEP efficacies in individuals unable to access PEP; PrEP costs significantly below current prices (through single-dose approaches, inclusion in childhood vaccination schedules, increased manufacturing volume and/or new low-cost products); and variable rabies exposure risk and PEP access. We also present results from a simplified model, designed for ease of understanding.

Results: Modelled ICERs were <1000 USD per quality adjusted life year (QALY) across a range of plausible combinations of rabies exposure risk, PEP access, PrEP cost and PrEP efficacy. If PrEP efficacy exceeds 50 % over 15 years, we estimate ICERs <500 USD/QALY where rabies incidence ≥3 per 100,000 per year and cost of vaccination is ≤5 USD/child. Under scenarios with lower rabies incidence of around 0.3 per 100,000 per year, due either to more limited exposure or greater access to PEP, ICERs <3000 USD may still be achieved even if PrEP efficacy is as low as 30 %.

Conclusions: Routine childhood PrEP may be cost-effective in settings with modest willingness-to-pay, and rabies exposure risks plausible across much of Africa and South Asia. Cost-effectiveness requires low-cost PrEP regimes and some efficacy of PrEP in individuals unable to access PEP. Under such conditions, PrEP may be an attractive additional tool in the fight against rabies.