An Australian scientist has said he discovered how to turn HIV against itself to stop it progressing to Aids.
A five-year study of HIV infected people is pointing the way for further work towards a vaccine.
A leader in the search for a vaccine against HIV said on Friday that recent advances have given scientists new reason for hope.
HIV/Aids vaccine researchers should move to smaller, more focused trials and dump any vaccines that do not show strong promise.
United States scientists have scrapped plans for a large trial of a HIV vaccine due to concerns about its effectiveness.
The Medical Research Council said South Africa's first HIV/Aids vaccine trials may start as early as February next year.
United States researchers have made progress in developing an Aids vaccine that would be effective against a range of strains of HIV.
Three million Aids deaths can be averted and more than 2,5-million HIV infections prevented by 2015 through voluntary testing.
Scientists believe they are a step closer to developing an effective Aids vaccine after studying an unexpected response to the HI virus.
The use of therapeutic vaccines was the major topic at the Immune Reconstitution and Control of HIV meeting in Italy last week.
The complex biology of the HI virus has posed constant challenges and even a partially effective vaccine is still some years away.