HIV hopes queried over cases in young Africans

Almost 25 years after the message on safe sex as a defence against Aids was conceived there are signs that it is getting through to the youth of Africa.

The number of young people infected with HIV has fallen by a quarter in 12 of the 25 worst-affected countries in the world, and is on a downward trend in four others, the joint United Nations programme on Aids reported today.

It is 15-24 year olds who are leading the “prevention revolution”, it says, by waiting longer to become sexually active, having fewer multiple partners and increasingly using condoms.

However, doubt was cast on the upbeat message by researchers yesterday. In South Africa, a 60 per cent reduction in HIV infections among women aged 15-24 between 2002-5 and 2005-8, reported in the journal Public Library of Science (PLoS) last month, has been criticised for its poor methodology, untested assumptions and for producing misleading results.

UNAIDs says in its latest “Outlook” report that there were 33.4 million people living with HIV worldwide in 2008, of whom 2.7 million became infected that year and 2 million died.

Despite the investment of billions of dollars over the last decade only five million of the 15 million people who need anti-retroviral treatment are currently receiving it.

Further gains against the pandemic could be made by simplifying treatment. UNAIDS calls for the development of a “smarter, better pill” that is less toxic and requires less monitoring which could save costs - currently twice as much as the pills themselves - and lead to expanded coverage. Trreatment with anti-retroviral drugs can cut transmission of the disease by more than 90 per cent.

UNAIDS says treating everyone with the drugs they need could cut new HIV infections by a third, as well as reducing the incidence of tuberculosis and malaria among those carrying HIV.

Offering treatment encourages people to come forward for testing, reducing the risk to others. Michel Sidibe, UNAIDS executive director, said: “For countries to reach their universal access targets and commitments [on anti-retroviral drugs] we must reshape the Aids response. Through innovation we can bring down costs so investments can reach more people.”

The report says HIV prevalence declined by 60 per cent in Kenya between 2000 and 2005. In Ethiopia it fell by 47 per cent in urban areas, based on testing pregnant women, and by 29 per cent in rural areas. Malawi, Namibia, Tanzania, Zambia, Zimbabwe and Cote d’Ivoire saw similar falls.

In South Africa, which has the highest number of HIV infected people, there is dispute over whether the disease is in retreat. The household survey by Thomas Rehle of the Human Sciences Research Council in Capetown, South Africa, showing a 60 per cent fall in infections in young women published in PLoS last month received wide publicity and was hailed as showing the country was on course to hit its ambitious target of halving HIV infections overall by 2012.

Till Bärnighausen, epidemiologist at the Africa Centre for Health and Population Studies, University of KwaZulu-Natal, said the findings were based on assumptions about the population, death rates from Aids and effects of treatment, which, if altered, could invalidate the results. Reported condom use had increased but other measures of sexual behaviour such as age of first sex and multiple partners had not.

"There is little evidence from other sources that HIV incidence is coming down [in South Africa]. The 60 per cent claim would be a huge success - we would like to see more evidence to give it plausibility. What could have triggered such a reduction after so long with no change? It is dangerous to make such a strong claim because it could lead to a switch of focus from prevention to treatment or a decision not to increase funding for HIV for a group that still needs a lot of focus. Women report an increase in condom use but it could be women reporting that, not using them. Other measures of behaviour have not changed such as age of sexual debut and the number of women having more than one sexual partner. There is one outstanding report of increased condom use but not much evidence that other sexual risk taking has changed."

Referring to the PloS study, he added: “My strong feeling is that with some changed assumptions, the significance and size of the finding would have disappeared. Many senior colleagues here feel we should write a letter [to the journal] outlining our scientific criticisms vigorously.”