The intriguing tale of Zimbabwe’s apparent incremental victory over HIV continues, with the United Nations saying that the course of the disease in South Africa’s troubled neighbour appears to have been altered.
In a UNAids report titled Evidence for H5V Decline in Zimbabwe: A Comprehensive Review of the Epidemiological Data, released on Thursday, the organisation says Zimbabwe has seen a fall in the prevalence, or level of existing HIV infections, over the past few years. A more startling claim is that the country has also seen a decline in incidence, or the rate of new infections. It is estimated that one in five adult Zimbabweans is HIV-positive.
The report attributes some of the change to increased condom use and a decline in the number of sexual partners.
The multimillion-dollar questions for governments, donors and prevention campaigns are what triggered this behavioural change, and how can it be replicated in other countries. Is the behavioural change due to education interventions or more negative forces, such as sexual networks being constrained by the poor economic situation or the migration of “sugar daddies” who are no longer around to infect younger women?
While asserting that the levels of HIV infection did fall, the report admits that the reasons are obscured. It points out that the decline in prevalence cannot “be taken as evidence for the success of HIV prevention programmes”. The authors also point out that the apparent success may only be temporary.
The backbone of the evidence is the levels of HIV prevalence among pregnant women attending antenatal clinics, which has fallen from 26% in 2002 to 21% in 2004. But, while hailing the good news, the report notes that “there were a number of inconsistencies and biases in the data and the extent of the decline may not be quite as great as is indicated”.
The author of the study, Dr Simon Gregson from Imperial College, London, acknowledges the high levels of sceptism. But, having analysed all available research, he is convinced that the epidemic has been slowed, and that at least part of this is due to increased condom use and a reduction in the number of sexual partners.
The analysis in the report will be closely examined, particularly the causal links drawn. Sceptics have suggested that falling prevalence may indicate an increase in Aids-related deaths, given the high levels of malnutrition and poverty and the lack of medical supplies. Under-reporting of mortality may be fuelling the fall in prevalence.
Researchers in Zimbabwe are, however, adamant that, even taking these and other factors into account, the spread of HIV was slowed in the period under review.
Dr John Hargrove of the Zimbabwe Vitamin A for Mothers and Babies trial says research in Harare suggests that HIV prevalence had been declining at 9,5% a year since 1998, and that this is likely to be mirrored to some extent in the general population.
He is also confident that condom usage has increased, not just because of the greater number of condoms being distributed, but also because more than half are now being bought — and bought condoms are more likely to be used.