The cost-effectiveness of typhoid Vi vaccination programs: Calculations for four urban sites in four Asian countries

The burden of typhoid fever remains high in impoverished settings, and increasing antibiotic resistance
is making treatment costly. One strategy for reducing the typhoid morbidity and mortality is vaccination
with the Vi polysaccharide vaccine.We use awealth of neweconomic and epidemiological data to evaluate
the cost-effectiveness of Vi vaccination against typhoid in sites in four Asian cities: Kolkata (India), Karachi
(Pakistan), North Jakarta (Indonesia), and Hue (Vietnam). We report results from both a societal as well
as a public sector financial perspective.

Baseline disease burden estimates in the four areas are: 750 cases per year in twoKolkata neighborhoods
(pop 185,000); 84 cases per year in the city of Hue (pop 280,000); 298 cases per year in two sub-districts in
North Jakarta (pop 161,000), and 538 cases per year in three squatter settlements in Karachi (pop 102,000).
We estimate that a vaccination program targeting all children (2–14.9) would prevent 456, 158, and 258
typhoid cases (and 4.6, 1.6, and 2.6 deaths), and avert 126, 44, and 72 disability-adjusted life years (DALYs)
over 3 years in Kolkata, North Jakarta and Karachi, respectively. The net social costs would be US$160 and
US$549, per DALY averted in Kolkata and North Jakarta, respectively. These programs, along with a similar
program in Karachi, would be considered “very cost-effective” (e.g. costs per DALY averted less than per
capita gross national income (GNI)) under a wide range of assumptions. Community-based vaccination
programs that also target adults in Kolkata and Jakarta are less cost-effective because incidence is lower
in adults than children, but are also likely to be “very cost-effective”. A program targeting school-aged
children in Hue, Vietnam would prevent 21 cases, avert 6 DALYs, and not be cost-effective (US$3779 per
DALY averted) because of the low typhoid incidence there.