Evaluating Investments in Typhoid Vaccines in Two Slums in Kolkata, India.

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

Costs of illness due to typhoid fever in an Indian urban slum community: implications for vaccination policy.

Data on the burden of disease, costs of illness, and cost-effectiveness of vaccines are needed to facilitate the use of available anti-typhoid vaccines in developing countries. This one-year prospective surveillance was carried out in an urban slum community in Delhi, India, to estimate the costs of illness for cases of typhoid fever. Ninety-eight culture-positive typhoid, 31 culture-positive paratyphoid, and 94 culture-negative cases with clinical typhoid syndrome were identified during the surveillance. Estimates of costs of illness were based on data collected through weekly interviews conducted at home for three months following diagnosis. Private costs included the sum of direct medical, direct non-medical, and indirect costs. Non-patient (public) costs included costs of outpatient visits, hospitalizations, laboratory tests, and medicines provided free of charge to the families. The mean cost per episode of blood culture-confirmed typhoid fever was 3,597 Indian Rupees (US$ 1=INR 35.5) (SD 5,833); hospitalization increased the costs by several folds (INR 18,131, SD 11,218, p<0.0001). The private and non-patient costs of illness were similar (INR 1,732, SD 1,589, and INR 1,865, SD 5,154 respectively, p=0.8095). The total private and non-patient ex-ante costs, i.e. expected annual losses for each individual, were higher for children aged 2-5 years (INR 154) than for those aged 5-19 years (INR 32), 0-2 year(s) (INR 25), and 19-40 years (INR 2). The study highlights the need for affordable typhoid vaccines efficacious at 2-5 years of age. Currently-available Vi vaccine is affordable but is unlikely to be efficacious in the first two years of life. Ways must be found to make Vi-conjugate vaccine, which is efficacious at this age, available to children of developing-countries.

A cost-benefit analysis of typhoid fever immunization programmes in an Indian urban slum community.

Many economic analyses of immunization programmes focus on the benefits in terms of public-sector cost savings, but do not incorporate estimates of the private cost savings that individuals receive from vaccination. This paper considers the implications of Bahl et al.'s cost-of-illness estimates for typhoid immunization policy by examining how community-level incidence estimates and information on distribution of costs of illness among patients and the public-health sector can be used in the economic analysis of vaccination-programme options. The findings illustrate why typhoid vaccination programmes may often appear to be unattractive to public-health officials who adopt a public budgetary perspective. Under many plausible sets of assumptions, public-sector expenditure on typhoid vaccination does not yield comparable public-sector cost savings. If public-health officials adopt a societal perspective on the economic benefits of vaccination, there are many situations in which different vaccination programmes will make economic sense. The findings show that this is especially true when public decision-makers recognize that (a) the incidence of typhoid fever is underestimated by blood culture-positive cases and (b) avoided costs of illness represent a significant underestimate of the actual economic benefits to individuals of vaccination.