Sunday Times (Johannesburg) - May 29, 2005
Claire Keeton

WITS scientists have succeeded in identifying people in the most contagious stage of HIV in a study at a clinic in Hillbrow.

The groundbreaking study, which uses a new testing strategy, highlights the importance of early detection of the virus in the prevention of HIV.

It also paves the way for a new, cheaper system of testing.

The strategy used in the study detects the virus during the first three weeks of infection - the "window period" when standard tests fail to pick up HIV.

The new system picked up 12 cases of "highly contagious acute HIV infection" missed by the standard tests.

Standard tests check for antibodies that are not present in the first stage of infection.

The study also found that 672 people, or 35%, of the study group were HIV positive using standard tests.

Dr Francois Venter, the clinical director of the Wits Reproductive Health and HIV Research Unit at the Esselen Street clinic, said early detection can help reduce risky behaviour.

"We can make people aware they are highly infectious and that they must use condoms at the very least."

The window period is the most dangerous time for spreading HIV since transmission risks rise to roughly one in 50 acts of sexual intercourse.

Few newly infected people have symptoms or, if they do, their flu-like symptoms are mild.

The researchers at the clinic enrolled 1906 patients coming in for sexually transmitted diseases and voluntary counselling and testing between April and October 2004.

About half were men and the testing was conducted anonymously.

Professor Wendy Stevens of the National Health Laboratory Services and head of Molecular Medicine and Haematology at Wits, led the study together with Venter.

The scientists screened pools of blood samples provided by the volunteers at the Hillbrow clinic using NAT (nucleic acid testing).

This measures the actual virus in the blood.

Positive pools were broken down for further testing which is cheaper than using NAT for each sample.

The South African National Blood Transfusion Service will implement the new testing technology for individual samples from October.

Another benefit of swift HIV diagnosis is that patients may get better treatment.

US infectious diseases expert Professor Myron Cohen said: "In the first few weeks we can try to prevent HIV developing.

"With very aggressive therapy we have the chance to reduce or try to eliminate the latest pool of HIV."

This approach - to eradicate HIV before it does damage - could be one of the next frontiers of HIV science and South African researchers will collaborate on it.

The results of the study will be presented at an Aids conference in Brazil next month.

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