Africa's biggest HIV vaccine trial were stopped today (21 September) after a sister study testing the same experimental vaccine in US men found no protection against infection.
Glenda Gray, from the Chris Hani Baragwanath Hospital in Johannesburg, South Africa, and a lead researcher with the Phambili vaccine trials, confirmed that 700 volunteers from five sites in South Africa had already begun a series of three injections spaced over 12 weeks.
''Not one volunteer has been put at risk or harmed in any way,'' she emphasised.
The South African tests, intended to recruit 3000 people, have been ''paused'' until local researchers have studied the American data, based on men who have sex with men.
''This is a good sign in a way,'' Gray told SciDev.Net. ''This virus is elusive. We learn from these setbacks. We learn new ways, new ideas about to find a vaccine. We change our strategies as we learn more."
But Gray also said the stoppage was ''a tragedy which has put us back twenty years''.
The Phambili tests were "the largest vaccine trial so far in South Africa and in Africa", according to microbiologist Koleka Mlisana of the Centre for the AIDS Programme of Research in South Africa (CAPRISA). The vaccine was based on an adenovirus — the common cold virus — so carried no risk of transmitting HIV itself.
This week (17–19 September) the Bio2Biz biotechnology conference in Cape Town heard that only one HIV vaccine, in Thailand, has progressed to the final stage, phase III clinical trials.
Jim Sherwood, of the Johannesburg offices of the International AIDS Vaccine Initiative (IAVI), said the lack of progress was a "sad state". But he praised researchers for ''casting a wider net'' by using second level phase II trials to check vaccine effectiveness earlier.IAVI's introductory double vaccine trial — which uses naked DNA and a different type of adenovirus from the Phambili vaccine — was originally due to begin next week in Kenya, Rwanda, Uganda and Zambia. It, too, may be delayed while researchers study the US data.