Trials of a potential Aids vaccine for Africa have begun with human volunteers in Uganda, one of the worst hit countries on the continent, it was announced yesterday.
The vaccine is specifically designed to combat the A strain of the HIV virus, which is the type prevalent in east Africa. Most potential vaccines are focussed on the B strain found in the USA and Europe, although it is thought possible that a vaccine for one strain may be adaptable to fight another.
The DNA-MVA vaccine was designed by scientists at Oxford University, led by Professor Andrew McMichael, in collaboration with the University of Nairobi. Trials are already underway in the UK and in Kenya.
The latest trials are being run by the Uganda Virus Research Institute with the backing of the International Aids Vaccine Initiative (IAVI), a not-for-profit organisation set up to channel funds into promising projects. Volunteers at low risk of becoming infected with the virus have been injected with the vaccine to test its safety. ”The trials will go on for about two years after which we hope we can move it to the …next phase,” said principal researcher Pontiano Kaleebu.
IAVI is backing a number of different approaches to the extremely difficult task of developing a vaccine against a virus that invades the immune system, which should be the body’s defence. The Oxford-Nairobi vaccine is in fact two in combination, both made from copies of a selection of HIV genes which are incapable of forming the fully-functional virus. In the first, the genes are stitched into a ring of DNA and in the second, they are administered in a modified virus (MVA) with no relation to HIV and rendered harmless so that it does not itself cause disease.
The vaccines are intended to boost the immune system to produce cells that can seek out and destroy others which have been taken over by HIV. The idea came from researchers who discovered that a small group of commercial sex workers in Kenya had some immunity to HIV, even though they were regularly infected.
The trials are hugely important to sub-Saharan Africa, where 29,4-million people are infected with HIV. Uganda mounted one of the earliest and most successful prevention campaigns, with education and condom promotion, but half a million have died and 1,5-million are thought to be infected with HIV.
”Uganda is leading the way in the search for an Aids vaccine for Africa. It is important that the fruits of our work here be available to Ugandans as soon as a successful vaccine is created. Our agreement with IAVI ensures that a successful vaccine from this partnership will be made available in our country as soon as possible,” said Professor Francis Omaswa, Director General of the country’s health services.
Most agree, however, that an effective Aids vaccine is still some years off. There are three basic phases in the clinical trials: to establish that a vaccine or medicine has no damaging side-effects and then to test whether it works first in a small group of volunteers and then in a large number. The Uganda trials are still at first base, while other arms of the Oxford-Nairobi venture have only just moved into phase two.
Only one vaccine, AIDSVAX, has completed all three stages of clinical trials. After three years, the results are due at the end of next month. – Guardian Unlimited Â