Modelling the impact and cost-effectiveness of the HIV intervention programme amongst commercial sex workers in Ahmedabad, Gujarat, India

A dynamic mathematical model was used with survey and intervention-specific data from Ahmedabad to estimate the HIV impact of the Jyoti Sangh project for the 51 months between the two CSW surveys. Uncertainty analysis was used to obtain different model fits to the HIV/STI epidemiological data, producing a range for the HIV impact of the project. Financial and economic costs of the intervention were estimated from the provider's perspective for the same time period. The cost per HIV-infection averted was estimated.Over 51 months, projections suggest that the intervention averted 624 and 5,131 HIV cases among the CSWs and their clients, respectively. This equates to a 54% and 51% decrease in the HIV infections that would have occurred among the CSWs and clients without the intervention. In the absence of intervention, the model predicts that the HIV prevalence amongst the CSWs in 2003 would have been 26%, almost twice that with the intervention. Cost per HIV infection averted, excluding and including peer educator economic costs, was USD 59 and USD 98 respectively.This study demonstrated that targeted CSW interventions in India can be cost-effective, and highlights the importance of replicating this effort in other similar settings.The HIV epidemic in India is no longer negligible, with an estimated 5.7 million people living with HIV in 2005 (0.91% of the adult population) [1]. Although the overall prevalence in India may be below 1%, in the southern states of Andhra Pradesh, Karnataka and Maharashtra, and the north-eastern states of Manipur and Nagaland, the ante-natal clinic prevalence is above 1% [2]. In Gujarat the prevalence is generally much lower (0.13% among ante-natal clinic attendees in 2004). However, in the city of Ahmedabad, the HIV prevalence in 2003 amongst ante-natal clinic attendees was 0.75%, and was 13.2% amongst CSWs [3,4]. This is particularly concerning since Ahmedabad is the seventh largest city in India with a population of over 4.5 million in