A review of the economics of the prevention and control of rabies. Part 1: Global impact and rabies in humans

Abstract

The existing literature on the economics of rabies and its control can be characterised as a poorly documented set of cost estimates with insufficient information to allow replication of the analyses. Most articles have numerous 'violations' of the standard recommended procedures for assessing the burden of disease and the cost and benefits of interventions. Per capita costs are often crudely extrapolated from small to large populations without allowing for geographic differences in incidence. Furthermore, most studies do not distinguish between financial charges and true economic costs, and only a few articles contain a multiyear framework, complete with discounting of future costs and benefits. With the exception of the increase in average incidence of postexposure prophylaxes (PEPs) in Asia, the average incidences of both human-rabies cases and PEPs in Africa, the Americas and Europe have not changed significantly over time. There are, however, large differences between countries within a region and regional averages can conceal notable changes in incidences over time for a given country. The largest number of human-rabies cases occur in developing countries due to the low levels of vaccination among dogs, the high cost of biologicals for PEP and problems of availability. The costs (1995 values) of PEP range from $US1707 per person in Massachusetts, US, to $US2.50 for a complete series of vaccinations (without immunoglobulin) using sheep-derived vaccines in Karachi, Pakistan. Most studies which reported the cost of PEP, however, provided only direct medical costs and did not consider indirect costs such as lost productivity due to death, permanent disability or time spent while receiving medical care. Given the expense of controlling rabies in dogs and wildlife, there is an urgent need to develop a cheaper human-rabies vaccine or further refine the 'low-dose' PEP regimes. PEP is often given unnecessarily, and experience with expert consultations systems and algorithms has shown that the rate, and therefore total cost, of PEP can be significantly reduced. However, because it may be difficult to identify lesions from a bite by a bat, algorithms may be of less value when dealing with possible exposure to bat rabies. Using US prices and values, only 2 individuals per 1000 possible contacts have to be at risk from bat rabies in order for it to be economically justifiable to give PEP to all those potentially exposed to bat rabies. With regard to pre-exposure vaccination, routine use of pre-exposure has generally not been shown to be cost effective.