World AIDS Vaccine Day - still major challenges in search for a vaccine

The search for an HIV/AIDS vaccine has been "much more difficult than anyone expected", the International AIDS Vaccine Initiative (IAVI) admitted on Thursday, World AIDS Vaccine Day. Despite recent progress, "major challenges remain", IAVI said in a statement. These challenges were even more pronounced in Africa, where vaccine candidates were being tested in Botswana, Kenya, South Africa, Uganda and Malawi, said Dr Pontiano Kaleebu, a leading researcher with the Uganda Virus Research Institute. All the vaccine trials "still have a long way to go", as most of them were only in "phase one", Kaleebu told PlusNews. There are three phases in human clinical trials: Phase one involves 20-60 healthy, uninfected volunteers at low risk of HIV infection, and tests for safety. In South Africa, findings from two first-phase trials - currently being conducted in the port city of Durban and the Johannesburg township of Soweto - are expected to be released later this year. Nevertheless, with Rwanda, Tanzania and Zambia about to start tests on more vaccine candidates, the pace was slowly picking up. "In all these countries [with vaccine trials] the atmosphere is exciting; there is growing political support, and communities are becoming interested in what is happening," Kaleebu noted. But there were still "a lot of scientific issues" that presented obstacles. The regulatory process in most African countries is slow and sometimes non-existent, as guidelines for this type of research are still being defined. For instance, in Uganda it took two years and 9 committees to approve the vaccine trials conducted there, as there were no set procedures, he commented. Inadequate capacity was also a major problem, and many of the countries about to embark on vaccine trials had to "start from scratch" by developing a physical infrastructure of clinics, laboratories and state-of-the-art technology. This was particularly difficult in areas where basic services, such as power and water, were not easily available, Kaleebu pointed out. Researchers were also grappling with which type of candidate vaccine to produce, as most of the those currently being tested were designed "to induce just one type of immune response", IAVI said. "A highly effective AIDS vaccine will likely elicit a combination of immune responses: first, broadly neutralising antibodies to block HIV from entering cells; second, cell-mediated immune responses to destroy cells that HIV infects," the statement explained. Michelle Galloway, a spokeswoman for the South African AIDS Vaccine Initiative (SAAVI), admitted that the trials in Africa were only in the "very early stage of testing". But "laying the groundwork" by preparing communities for the larger trials, was equally important, she stressed. Communities had to be mobilised, not just to become volunteers but also to be informed about the complex research process taking place. Galloway said: "A lot of education [still] needs to happen ... people need to understand why this is taking so long, because people expect it to happen overnight. They also need to become involved through community advisory boards."