Sub-Saharan Africa is likely to have at least 1 million to 2 million new HIV infections each year for the next 10 to 20 years

Shashank Bengali:

The factors driving the region’s “hyper-epidemic” included a large population of migrant workers and low levels of male circumcision, which experts believe helps reduce HIV transmission. Sexual mores also played a major role: African men tend to have more long-term, concurrent sexual relationships than do men elsewhere, and they rarely use condoms in those relationships.

But the conditions are different in other regions of the world. In India, closely watched because its HIV-infected population of 5.2 million is by far the largest outside Africa, the virus has spread much more slowly than predicted, in part because Indian women appear to have fewer sex partners.

In China, officials recently revised the estimated number of total HIV infections downward — from 840,000 people to 650,000. The epidemic has stayed mostly confined to intravenous drug users and prostitutes, and United Nations projections from earlier in the decade that as many as 10 million people would be infected by 2010 now seem wildly overstated.

“There were very dramatic words a couple of years ago about India, about China, about what was coming — tremendously alarmist words,” said Stephen Lewis, the U.N. secretary-general’s special envoy for HIV/AIDS in Africa. “And it doesn’t seem to have happened.”

While mathematical models suggest that the spread of HIV is slowing, it is impossible to say for sure. AIDS symptoms don’t show up for several years, so the newly HIV-infected often don’t know they have HIV.

Even if HIV has peaked, there is little cause to celebrate, researchers say.

For one, the rates of new infections in some countries remain horrendously high. Sub-Saharan Africa is likely to have at least 1 million to 2 million new infections each year for the next 10 to 20 years, said James Chin, a professor at the University of California, Berkeley, who is the author of a forthcoming book on the AIDS pandemic.

For another, the slowdown may simply mean that in some countries most of the people likely to be infected already are infected, so the pool of at-risk people has shrunk.

HIV origin 'found in wild chimps'

Source of HIV virus traced to chimps from Cameroon