BioEd Online

Strife-torn Zimbabwe may have scored a blow against the deadly virus that causes AIDS.

Researchers of the disease report that prevention programmes have cut the portion of Zimbabweans infected with the human immunodeficiency virus (HIV) by 2.5%. The news has inspired those hoping that education campaigns advising people to change their behaviours could turn back the scourge of AIDS in Africa.

“This is the first time we’ve had reliable, convincing evidence from southern Africa that HIV prevalence is beginning to fall,” said Richard Hayes, an epidemiologist at the London School of Hygiene and Tropical Medicine. “This is very encouraging news.”

Good news is sorely needed in the fight against AIDS in Africa where, according to the World Health Organization, about 25 million people are infected with HIV.

Dangerous sex

Between 1998 and 2003, the researchers asked thousands of Zimbabweans questions about their sexual behaviours, and tested them for HIV infection.

During the five-year study, the researchers found that infection rates dropped from an average of 23% to 20.5%. The greatest reduction was seen in young people, who were waiting longer to have their first sexual encounter. And adults said they were having sex with fewer partners. Condom use by women during casual sex also went up from 26.2% to 36.5%; male condom use stayed at about 42% over the 5-year period.

This combination of behavioural changes most likely led to the decline in infection, says Simon Gregson, a demographer at Imperial College London who conducted the study with colleagues from London, Zimbabwe and South Africa. Many other countries are employing similar strategies to try to change peoples’ behaviours.

“Perhaps one of the most interesting things is that the greatest behaviour change was in abstinence and fidelity. The relative change in condom use was not as remarkable,” says Mark Dybul, the Deputy US Global AIDS Coordinator.

But Gregson says it is important to note that all three types of behaviour change seem important in Zimbabwe. “We need to be promoting all the different prevention possibilities,” he says.

Reason to hope

During the late 1990s, Uganda reported the continent’s first signs of a drop in HIV-infection rates; rates of HIV infection in pregnant women reporting to health clinics later showed a decline (see ‘ Uganda’s HIV epidemic wanes’).

The country’s leaders attributed much of this success to their ‘ABC’ prevention strategy, which stands for abstinence, being faithful, and condom use. But others have worried that Uganda’s apparent decline in HIV-infection rates may have been due to the death of infected individuals.

There are now signs that the overall portion of Uganda’s population infected with the virus is leveling off or even climbing back up.

Hayes notes that the Zimbabwe study is based on a wide variety of men and women from different social and economic classes in twelve different towns. This makes it more robust than the previous indications of an HIV-infection decline.

He adds that as drugs to treat AIDS become more prevalent and affordable, health workers must be on their guard to ensure that people do not become complacent and revert to old habits. “Other countries have seen a resurgence after the fall, so one has to work very rigorously to try and maintain these reductions,” Hayes says. “In the era of antiretroviral treatments, it’s become more important, not less, to emphasize prevention.”

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