Impact of an intensive HIV prevention programme for female sex workers on HIV prevalence among antenatal clinic attenders in Karnataka state, south India: An ecological analysis

Objectives: To examine the impact of an intensive HIV preventive intervention (IPI) among female sex workers (FSW) on community HIV transmission, as represented by HIV prevalence among young antenatal clinic (ANC) attenders in Karnataka state, south India. Methods: The IPI was initiated in 18 of the 27 districts in Karnataka in 2003, and was generally at scale by mid-2005, covering over 80% of the urban FSW population. We examined trends over time in HIV prevalence from annual HIV surveillance conducted among ANC attenders in Karnataka under the age of 25 years from 2003 to 2007, comparing the IPI with the other districts. Results: Overall, HIV prevalence among ANC attenders under 25 years of age declined from 1.40% to 0.77%. In a multivariate model, the decline in HIV prevalence in the IPI districts compared to the other districts was statistically significant (P=0.01), with an adjusted annual odds ratio of 0.88 (95% CI 0.79-0.97). The decline in standardized HIV prevalence in the IPI districts over the period was 56%, compared to 5% in the non-IPI districts. Conclusions: Although this analysis is limited by lack of precise comparative data on intervention coverage and intensity, it supports the notion that scaled-up, intensive, targeted HIV preventive interventions among high-risk groups can have a measurable and relatively rapid impact on HIV transmission in the general population, particularly young sexually active populations as represented by ANC attenders. Such focused intervention programmes should be rapidly taken to scale in all HIV epidemics, and especially in concentrated epidemics such as in India.