This article considers the investment case for using the Vi polysaccharide vaccine in developing countries
from two perspectives: reducing typhoid cases and limiting new health care spending. A case study is
presented using data fromSouth and Southeast Asia. The purpose of the paper, however, is to drawbroad
implications that may apply to developing countries in general. Typical consumer demand functions
developed from stated preference household surveys in South and Southeast Asia are used to predict
probabilities of adults and children purchasing typhoid vaccinations at different prices. These functions
are incorporated in a formal mathematical model.
Using data from the recent literature for South and
Southeast Asia for typhoid incidence, Vi vaccine effectiveness, public cost of illness, and vaccination
program cost, three mass vaccination policy alternatives are evaluated: charging adults and children
different (optimal) prices, charging uniform prices, and providing free vaccines. Assuming differential
pricing is politically feasible, different vaccine prices for children and adultswould maximize the number
of typhoid cases avoided froma mass vaccination program if the public sector faces a budget constraint on
spending for the vaccination program. However, equal prices for children and adults produce very similar
results, and they might be more readily accepted by the community. Alternatively, if vaccines are free,
the number of cases is not significantly reduced compared to either pricing policy, but a large external
financial contribution from government or donorswould be required. A Monte Carlo simulation explores
the effects of uncertain parameters on vaccination program outcomes.
