Methods: We compared three strategies: no vaccination, 1- and 2-dose vaccination with Rotarix - a new live attenuated rotavirus vaccine. We assumed the doses would be administered through an existing immunization program with known coverage rates. Published cumulative incidences of infection were used to generate interval-specific probabilities of infection. These probabilities were revised according to vaccination status using efficacies from a clinical trial. Since no trials of Rotarix in Asia have been completed, efficacies were estimated using India-specific strain distributions and known strain-specific vaccine efficacies. Conditional probabilities for hospitalization and mortality were derived from population figures. Baseline vaccine cost used was $7/dose, the wholesale price recently paid by Brazil. We varied this parameter from $1 to $50. A recent trial evaluating treatment of diarrhea in Indian children provided most treatment cost data. Since the quality-of-life impact was over such a short period of time in relation to life expectancy of an infant, we used life-years saved (LYS) as our effectiveness measure. The conservative cost-effectiveness criterion used was $3,300 US (1 x India's estimated 2005 per capita GDP) per LYS.
Results: Baseline analysis yielded an incremental cost-effectiveness ratio (ICER) of $170.56 per LYS for moving from a strategy of no vaccination to a strategy of one dose of Rotarix, and an ICER of $350.77 per LYS for moving from one to two doses. This corresponded to estimated annual mortality reduction of 25,555 (27.0%) for one dose and 37,369 (39.5%) for two doses. Estimated India-specific vaccine efficacies used were 50.6% against any infection and 59.7% against severe infection (versus 72% and 85%, respectively, from a trial in Finland). 2-dose vaccination was preferred in one-way sensitivity analyses of all variables. Threshold vaccine costs per dose for 1- and 2-dose strategies were $133.13 and $65.25. For a 2-dose strategy, vaccination remained cost-effective at efficacies as low as 6.25% against any infection and 7.35% against severe infection.
Conclusions: Until there is a Rotavirus vaccine made from strains isolated in India, Rotarix appears to be a cost-effective and lifesaving intervention. This is despite the fact that differences in endemic strains would likely make Rotarix less effective in India than trial data might suggest.