New Delhi: It was reported to be the best chance to prevent the HIV virus. Test results of a combination vaccine - a collaboration between the US army and Thai researchers - was found to cut the risk of infection by almost one-third.
Human clinical trials were carried out on nearly 16,000 healthy Thai volunteers, but a second and third analyses of the trials have been disappointing. Findings show just 26 per cent protection against HIV - low enough to be attributed to chance.
Senior Consultant, Internal Medicine, Max Hospital, Dr Monica Mahajan says, "This simply means that out of every four people vaccinated with booster shots, three end up getting HIV, so it's no protection at all. People will live in fear wondering which ones can give protection and which ones will infect."
The volunteers were divided in two groups for the vaccine trial.
Fifty-one volunteers who received the combination vaccine got infected with HIV, compared to 74 who received a placebo. No one monitored the sexual activities of the volunteers in the three years that the human trial was on.
The distribution of volunteers wasn't uniform and it is not known whether both groups of volunteers had an equal number of people at the same risk of getting HIV.
The $120 million project had been criticised when it was launched six years ago as each of the components of the combination vaccine had failed individually in earlier trials.
ALVAC - one of the vaccines - was developed by Sanofi Aventis in Paris. The other vaccine, was AIDSVAX and was created by Genetech Inc.
Editor, Monthly Index of Medical Specialties, Dr C M Gulati says, "They were working on a concept of putting two vaccines together and trying their effectiveness. In medicine, two components could have been more effective, but this particular trial failed in that concept."
But all is not lost yet for the billions of people at risk of HIV. Even after 25 years of anti-aids vaccine trials that have not been fruitful, there are still 28 other vaccine candidates in the pipeline.