Suchergebnisse

New-generation vaccines against typhoid fever have the potential to reduce the burden of disease in areas where the disease is endemic. The case for public expenditure on typhoid Vi polysaccharide vaccines for two low-income, high-incidence slums (Narkeldanga and Tiljala) in Kolkata, India, was examined. Three measures of the economic benefits of the vaccines were used: private and public cost-of-illness (COI) avoided; avoided COI plus mortality risk-reduction benefits; and willingness-to-pay (WTP) derived from stated preference (contingent valuation) studies conducted in Tiljala in 2004. Benefits and costs were examined from a social perspective. The study represents a unique opportunity to evaluate typhoid-vaccine programmes using a wealth of new site-specific epidemiological and economic data. Three typhoid-vaccination strategies (targeting only enrolled school children, targeting all children, and targeting adults and children) would most likely pass a social cost-benefit test, unless benefits are restricted to include only avoided COI. All three strategies would be considered 'very cost-effective' using the standard comparisons of cost per disability-adjusted life-year avoided with per-capita gross domestic product. However, at an average total cost per immunized person of ∼US$ 1.1, a typhoid-vaccination programme would absorb a sixth of existing public-sector spending on health (on a per-capita basis) in India. Because there appears to be significant private economic demand for typhoid vaccines, the Government could design a financially-sustainable programme with user-fees. The results show that a programme where adults pay a higher fee to subsidize vaccines for children (who have higher incidence) would avoid more cases than a uniform user-fee and still achieve revenue-neutrality.

Although it is well known that vaccines against many infectious diseases confer positive economic externalities via indirect protection, analysts have typically ignored possible herd protection effects in policy analyses of vaccination programs. Despite a growing literature on the economic theory of vaccine externalities and several innovative mathematical modeling approaches, there have been almost no empirical applications. The first objective of the paper is to develop a transparent, accessible economic framework for assessing the private and social economic benefits of vaccination. We also describe how stated preference studies (for example, contingent valuation and choice modeling) can be useful sources of economic data for this analytic framework. We demonstrate socially optimal policies using a graphical approach, starting with a standard textbook depiction of Pigouvian subsidies applied to herd protection from vaccination programs. We also describe nonstandard depictions that highlight some counterintuitive implications of herd protection that we feel are not commonly understood in the applied policy literature. We illustrate the approach using economic and epidemiological data from two neighborhoods in Kolkata, India. We use recently published epidemiological data on the indirect effects of cholera vaccination in Matlab, Bangladesh (Ali et al., 2005) for fitting a simple mathematical model of how protection changes with vaccine coverage. We use new data on costs and private demand for cholera vaccines in Kolkata, India, and approximate the optimal Pigouvian subsidy. We find that if the optimal subsidy is unknown, selling vaccines at full marginal cost may, under some circumstances, be a preferable second-best option to providing them for free. [Copyright 2009 John Wiley and Sons, Ltd.]