HIV infection rates have fallen by one-third in the worst hit regions of India, according to a new study published this week in "The Lancet" medical journal. The report's authors say their research proves that prevention works on a large scale.
The study, led by investigators at the Center for Global Health Research at the University of Toronto, focused on the effect of AIDS prevention measures southern India, which is the region of the country hardest hit by the disease.
Investigators say more than five million people in India are infected with the virus that causes AIDS. Three-quarters of them live in the southern part of the country.
Experts say that region of India is vulnerable to the spread of the virus because many males migrate there looking for jobs. The men visit HIV-positive prostitutes and later infect their wives.
To gauge the problem, researchers followed the medical histories of nearly 300,000 young women, visiting 214 pregnancy and post-delivery clinics in both the north and south between the years 2000 and 2004.
Prabat Jha is director of the Center for Global Health and co-author of the study. Jha says researchers found a one-third decrease in the number of new infections in southern India, which he called significant.
"So, it suggests that the epidemic at least has turned around in the south. That is the good news," he said. "The bad news is the north of India, where most of the population is, is really uncertain."
Researchers found no significant decline in HIV infection rates in clinics in the northern part of the country.
Investigators looked for a number of reasons that might account for the drop in the number of HIV infections in the south, such as the deaths of women with AIDS.
But Jha believes the drop is the result of prevention campaigns by the Indian government and the World Health Organization.
Karen Stanecki, a senior adviser at UNAIDS in Geneva, explains how the campaign works.
"The decline can be explained by increased condom use or increased abstinence, and that they have seen increased condom use among men who have gone to sex workers," she noted.
To Prabat Jha, the message is clear.
"Before this, we have seen some evidence, certainly from Thailand, but also from Cambodia and other places, that if you take prevention seriously, you can turn around the epidemic, in fact in a way that certainly treatment has not been able to nor will it likely be able to," he added.
The study recommends continued surveillance in southern India, where the gains are recent, and northern India, where there are few signs of progress.