Vaccine from horse disease to be tested in fight against African Aids epidemic

Doctors in South Africa and America are to launch the first human trial of an Aids vaccine using a disease affecting horses to combat the strain of the virus most prevalent in southern Africa.

Doctors in South Africa and America are to launch the first human trial of an Aids vaccine using a disease affecting horses to combat the strain of the virus most prevalent in southern Africa.

A total of 4.7 million people are infected with the Aids virus in South Africa, more than in any other country. One in nine South Africans, and one in four adults, is believed to be HIV positive.

The new vaccine was developed by an American biotech company, AlphaVax, in collaboration with a team of Cape Town virologists. It is a unique blend of the subtype C variant, the most common strain of the Aids virus in southern Africa, and a disease that commonly affects horses, known as Venezuelan Equine Encephalitis (VEE).

Although vaccine trials are under way in Uganda and Kenya, the trials in Durban involving 48 volunteers, and at a second site in America, will be the first to involve VEE.

Mark Colvin, an epidemiologist, said final plans for the first phase were in place and suitable candidates would soon be identified for testing. Those agreeing to participate would have to be free of HIV, not likely to contract it, and in good health. "It will be a random double-blind study," explained Dr Colvin "This means that some of the substances injected will not contain any vaccine. Neither doctor, nor patient will know who is receiving the active vaccine."

VEE is endemic in South and North America, Trinidad and Mexico. Horses, mules and humans are susceptible to the illness, with infection being transmitted by mosquitoes.

Carolyn Williamson, a virologist from the university of Cape Town, said: "The VEE coat is used for the delivery of the Aids vaccine and as it doesn't have all the ingredients to replicate itself, it is rendered not infectious. Once delivered, the machinery is in place to churn out volumes of HIV protein needed to get an immune response, which in turn will hopefully protect against infection."

The phase one trial is due to begin in March. It will be followed by two bigger studies.