Important note: Information in this article was accurate in 2009. The state of the art may have changed since the publication date.
Bangkok Post - July 22, 2009
Apiradee Treerutkuarkul
The results of the trial are expected to be announced in the next two months.
"We really don't know if the vaccine may or may not work. But it's going to be a big surprise if it does," Mitchell Warren, executive director of the Aids Vaccine Advocacy Coalition (Avac) said here on Monday at the International Aids Conference on HIV Pathogenesis, Treatment and Prevention.
"We don't even think it should have happened in the first place. The trial is very expensive and the product itself does not look good."
Avac is an international non-government organisation concerned about the global delivery of Aids vaccines and other HIV prevention options.
In 2003, up to 16,000 people in the eastern provinces of Chon Buri and Rayong were recruited to participate in the clinical study. Each volunteer was given either a vaccine or a placebo over a one-year period and followed up after at least 3-1/2 years, which ends in September.
The so-called "prime-boost" project involved two vaccines, Alvac created by France-based Aventis Pasteur and AidsVAX made by the California-based VaxGen Inc, to stimulate different immune response systems simultaneously.
The clinical trial in Thailand is the first time the two vaccines were combined as experts believed the combination was an effective alternative to HIV/Aids control. Previously, research projects in Africa had used only one vaccine at a time and the results were not satisfactory.
Some researchers have questioned the vaccine's validity, and the scientific ethics and efficacy of the trial because the two vaccines used in the Phase I and Phase II clinical trials were ineffective in preventing HIV transmission.
Mr Warren said the efficacy of the vaccine would be limited as it could only work against the Aids sub-types B and E existing in Thailand and other countries in the Southeast Asian region.
"If the vaccine proves successful, it will take years to make it available for the populations in the vaccine-test provinces, let alone the overall population."
The Food and Drug Administration will have to review safety and ethical aspects of the trial before giving the vaccine developers a licence for commercial production.
Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases, said vaccines should only be a part of other comprehensive interventions such as early antiretroviral treatment among HIV-positive people and the promotion of condom use undertaken among developing countries facing HIV/Aids problems.
Supachai Rerks-ngarm, chief researcher of the trial project, said at an Aids conference in Bangkok in May he was positive about the project.
"There is no real success or failure when it comes to vaccine trials," he said. "We know that one of the vaccines is not working. But the only way to learn from combinative vaccines is to do studies."
More than 5,000 Aids researchers have gathered in Cape Town for the four-day biannual scientific meeting amid growing concern over the global recession's impact on access to HIV prevention and treatment and scientific research on Aids.
See also: Making Medical History
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