African AIDS Vaccine Programme launched

CAPE TOWN — African scientists gathered in Cape Town this month to coordinate research into finding a cheap, effective and safe vaccine for the HIV strains common to Africa. The African AIDS Vaccine Programme (AAVP), set up under the auspices of the World Health Organization and UNAIDS, aims to coordinate the efforts of national vaccine research progammes with the goal of bringing a vaccine to market within ten years. "A vaccine for Africa would be the best long term preventative measure against AIDS," said Peter Piot, executive director of UNAIDS. "Enormous efforts should go into this initiative, which could help address the health and development tragedy that AIDS has become for many African countries."Although more than 28 million Africans are HIV positive, less than 2% of world research funding goes towards fighting the viral subtypes most common in Africa. Professor Malegapuru Makgoba, head of the Medical Research Council of South Africa, said, "It is unacceptable that the continent that is home to more than two thirds of all people living with HIV/AIDS receives so little attention."Delegates called for more vaccine trials to be carried out in Africa. Of more than 30 HIV vaccine trials conducted throughout the world since 1987 only two were carried out in Africa.Tim Tucker — head of the South African AIDS Vaccine Initiative (SAVI) — told The Scientist, "What tends to happen is that research focuses on where the money is. Much of the research has historically been in the United States and Europe looking at subtype B vaccine products because that is the predominant strain there. Subtype B is important, but is only a relatively small proportion of the AIDS burden. In southern Africa the main subtype is C and in fact more than 50% of new infections globally are of subtype C." He added, "We don't know whether a vaccine based on one subtype will protect against other subtypes, although eventually we hope to produce one vaccine that is effective against all subtypes."Early research into HIV vaccines has been disappointing. "There has been a shift in thinking and strategies over the last five years and we are now very optimistic that an effective HIV vaccine will be developed," Tucker explained.There are a number of grounds for this optimism. First, studies of non-human primates given candidate vaccines based on SIV (simian immunodeficiency virus) have shown either complete or partial protection against infection with the wild type virus. Second, successful vaccines have been developed against other retroviruses. Third, almost all humans develop some form of immune response to HIV infection, with some exposed people remaining uninfected or able to control the viral infection over long periods. The clearest example of this is a group of sex workers from Nairobi and South Africa who have remained HIV negative despite continuing high-risk exposure — this is thought to be due to their ability to mount protective immune responses to HIV, rather than any innate host genetic factors (J Immunol 2000, 164:1602-1611).Research into a subtype B HIV vaccine has already reached phase III testing in the US with the results expected later this year. But research into non-subtype B vaccines lags much further behind. Tucker says, "We, and others, have a number of candidate vaccines for subtype C and we are on the edge of moving between pre-clinical and clinical trials. We hope to start human volunteer trials later this year in South Africa. The average time to develop a vaccine is 20–25 years and we hope to halve this time."There are a number of reasons why research into AIDS vaccines in Africa has been slow to get off the ground. First, there needs to be the political will to take action. Governments frequently concentrate on short-term measures and ignore what could take ten or 15 years to bear fruit. Makgoba, writing in the British Medical Journal, stated, "An effective, affordable, and accessible HIV vaccine is within reach, within 7–10 years. If we fail to provide the world with an effective HIV vaccine, future generations will judge us harshly, because this failure will be due not to lack of ability or resources but to politics" (BMJ 2002, 324:211-213).The second major obstacle is one of economics. Vaccines have never been as commercially successful as other medical treatments, and so entering the field of HIV vaccine development is a risk for companies. The largest market for a vaccine will be in countries with a high prevalence. But these countries are also the poorest and so will not have the resources to buy and distribute the vaccine.In addition research infrastructures are often inadequate in Africa. The AAVP hopes to raise US$233 million, part of which will be used to build up regional facilities and strengthen local expertise. "Considering that the average cost of developing a new prescription drug in the United States is $800 million, $233 million to save many lives seems a very inexpensive price tag," said Yasuhiro Suzuki, executive director for health technology and pharmaceuticals at the World Health Organization.There are a number of other practical obstacles to conducting trials in developing countries. The first trial of the HIV-1 vaccine recently completed in Uganda encountered social, political, legal and ethical barriers to completing the trial, manifesting itself in widespread public and media fears about the risks of taking part in the trial, including the risks of becoming infected and being experimented on.Tucker added, "There are a number of cultural factors that need to be considered when carrying out research in Africa and elsewhere. For example, in some patriarchal societies women may not be able to give consent easily without the consent of their husbands."To those who question whether so much effort should be spent on vaccine research, when most of those already infected will die before the first vaccine is ready for production, Tucker says, "The best hope for eradicating, rather than simply controlling HIV, is to develop a vaccine."

African AIDS Vaccine Programme launched

New initiative aims to develop a vaccine against the HIV subtype most prevalent in Africa.

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