HIV infection rates down one-third in south India since 2000

HIV prevalence has declined by one-third since 2000 in the worst affected region of India, researchers from Canada and India report today in the online edition of The Lancet. The decline is attributed to a reduction in HIV transmission rather than deaths from AIDS, and the investigators say that increased condom use by men visiting sex workers is the most likely explanation for the decline, which is focused in southern India.

The study tracked HIV prevalence among 294,050 young women attending pregnancy or antenatal clinics in India's southern and northern states. Researchers used HIV trends among young women attending antenatal clinics between 2000 and 2004 as a proxy to monitor trends in new infections among the general population.

The study also monitored HIV prevalence among 58,790 men attending sexually transmitted infcetion (STI) clinics during the same period. Male use of female sex workers is the main reason for the spread of HIV in India, and use of sex workers is markedly higher in southern India. In recent years, the Indian government, the World Bank and other external agencies have aimed intervention and awareness programmes at the sex industry.

Results

The investigators found that HIV-1 prevalence among women aged 15-24 years in the south fell from 1.7% to 1.1% from 2000 to 2004 (absolute decline 0.6%; relative decline 35%). However a significant reduction was not seen in women aged 25-34 years.

For men aged 20-29 years attending STI clinics in the south there was an absolute reduction of 7.6% (relative reduction 36%) in HIV-1 prevalence.

No significant change in HIV-1 prevalence was seen among women or men in the north. The fall in the south was seen in rural and urban areas and in educated and illiterate men.

Explanations

India is estimated by its National AIDS Control Organisation to have 5.1 million people living with HIV, although some have criticised this figure as an underestimate. Three-quarters live in southern India. Several studies have estimated that the majority of infections in India still occur as a result of transmission from female sex workers to male clients. In 2004 11% of urban men reported that they regularly paid for sex.

"There have been many predictions, mostly based on guesswork, that India's AIDS problem will explode - as it did in southern Africa -- but we now have direct evidence of something positive," said the study's co-author, Professor Prabhat Jha of University of Toronto's Department of Public Health Sciences. "The good news is that HIV in young adults appears to be declining in the south - most likely or perhaps only due to males using sex workers less or using condoms more often when they do. The not-so-good news is that trends in the north remain uncertain and poorly studied."

Lead author Professor Rajesh Kumar at the Postgraduate Institute of Medical Education and Research in Chandigarh, India, says, "The declines in young women in the south are broad based -- for example, among urban and rural women and among educated or illiterate women. Moreover, declines in the south are seen also among young men who visit STI clinics and these men represent those who are likely to use sex workers. It all fits."

The study examined alternative explanations but changes in testing or in deaths from AIDS don't appear to explain the decline. "The first question we ask as scientists is if our findings are real and it appears they are," adds Jha, who is also the director of U of T's Centre for Global Health Research and a Canada Research Chair in health and development.

Paul Arora, a research fellow at the Centre for Global Health Research, says, "A key implication of the study is the need to scale up highly effective prevention efforts in the north, especially in hot-spot urban and rural districts -- not just for female sex workers but also for men having sex with men."

Kumar cautions that while the findings are good news, the battle is far from over. "HIV remains a huge problem in India and we have to remain vigilant," he says. "We're not saying the epidemic is under control yet -- we are saying that prevention efforts with high-risk groups thus far seem to be having an effect."