New research suggests that the number of fresh HIV infections in the world appears to have peaked, according to a report by leading AIDS researchers published Thursday in the British health journal The Lancet.
They cited evidence including a study, also published Thursday, that indicated that the number of pregnant women with HIV in southern India has declined by more than a third from 2000 to 2004.
The findings raise hopes that prevention programs are having a positive impact in the fight against AIDS, which has killed an estimated 25 million people. Rates of infection have remained high in areas including southern Africa, the epicenter of the pandemic, and the United Nations’ AIDS program estimates that about 5 million people are infected globally each year.
The analysis published in The Lancet by three veteran AIDS epidemiologists — two working for the U.S. Agency for International Development and one for the World Bank — said India and much of sub-Saharan Africa are seeing decline in rates of new infections. The two areas account for three-quarters of the world’s HIV cases.
Other countries showing a downward trend of infections, according to U.S. Census Bureau data and cited in the study, are Uganda and Zambia, where infections apparently peaked in 1987; Kenya in 1993; Botswana and Lesotho in 1994; and South Africa around 1997.
James D. Shelton, lead author of the analysis on HIV incidence and senior medical scientist at USAID’s bureau for global health, said the main reason for declines in new infections is rooted in the natural life cycle of disease outbreaks. He said individuals who are most susceptible to a virus tend to be infected first, and as time passes fewer people are as susceptible.
Epidemiologists believe that AIDS exploded in parts of eastern Africa and throughout southern Africa through sexual networks that included prostitution rings and men and women who had multiple partners. People with HIV, which causes AIDS, pass it on most readily soon after becoming infected and in their dying days.
But Shelton said a second reason for a reduction in new infections globally was rooted in various types of prevention.
He noted that programs aimed at changing the behavior of high-risk groups in Thailand and Cambodia, mostly intravenous drug users and sex workers, were a major factor in containing those outbreaks.
In West Africa, widespread male circumcision probably acted as a strong protective barrier, preventing the region from the galloping prevalence rates experienced in southern Africa, the researchers wrote.
And in areas of high rates of HIV infection, Shelton said, studies have shown some success for prevention programs — notably those promoting reduction of partners and effective condom use — to bring about reductions in HIV infections in Uganda, Kenya, Zimbabwe, Rwanda, Malawi, Ethiopia, and Haiti.
