Trial HIV vaccine leaves 46 infected

A failed clinical trial HIV vaccine that left 46 Zambian women infected with the virus has sparked controversy.

The Microbicides Development Programme (MDP) 301 trial, which was testing if the gel PRO2000 would prevent HIV infection took place between September 2005 and 2009.

It was conducted at six research centres in South Africa, Tanzania, Uganda and Zambia and 9,385 participated.

From the Zambian site in Mazabuka district – about 160 kilometres South West of the capital Lusaka – 1, 332

HIV negative women were recruited but the results, which the Ministry of Health does not wish to comment on, revealed that between 46 and 50 of women that participated in the clinical trial contracted HIV despite using PRO2000 gel before sex.

“Some participants did become HIV positive because the study was conducted in the normal environment,” confirmed Dr Maureen Chisembele, principal investigator for Microbicides Development Programme Zambia – a subsidiary of the UK based research entity. 

“Women who became infected during the study were given further counselling and referred to local health services for ART (antiretroviral therapy).”

The National Aids Council of Zambia (NAC), a government unit mandated to oversee HIV/Aids programme, confirmed that 50 out of the 1, 332 women that participated in the clinical trials contracted HIV.

Due to the sensitivity and repercussions of the issue, the Ministry of Health has remained tight-lipped on the outcome of the trials.

A vaginal microbicide is a product intended for use before sexual intercourse to reduce HIV infection and they are supposed to be used with condoms and complement other prevention strategies such as behaviour change, abstinence and other preventive methods.

It should be noted that vaginal microbicide should not be used alone or replace correct and consistent use of condoms in the fight against HIV and Aids, said Dr Swebby Macha – a gynaecologist at Zambia’s University Teaching Hospital (UTH) in Lusaka, the largest hospital in the country.

The participants in the clinical trial were either assigned the PRO2000 gel or placebo gel (with inactive ingredient) and were instructed to apply gel about one hour before sexual intercourse. 

The gel contains molecules that are intended to cluster around the virus before it can penetrate the vaginal wall.

To be effective, the women were counselled on safe sexual behaviour and encouraged to use condoms, which were provided free of charge.  

According to Dr Macha, this clinical trial found that the risk of HIV infection in women that were supplied with PRO2000 gel was not significantly different than women supplied with placebo gel.

“The largest international clinical trial to date into a preventive HIV gel has found no evidence that the vaginal microbicide, PRO2000, reduces the risk of HIV infection in women,” said Dr Macha, the former president of Zambia Medical Association (ZMA).

Dr Macha said to date no microbicide had been proved to be effective against HIV infection.

A local traditional ruler has demanded compensation for the infected women and prosecution of architects of the clinical trial.