Thailand wins praise for AIDS vaccine trial
An experimental AIDS vaccine that appears to be the first to protect people was mired for years in deep controversy, and credit for its success must go to Thailand where the trial was conducted, experts said.world Updated: Sep 28, 2009 12:14 IST
An experimental AIDS vaccine that appears to be the first to protect people was mired for years in deep controversy, and credit for its success must go to Thailand where the trial was conducted, experts said.
The trial was criticised by 22 prominent U.S. scientists in 2004 because the vaccine was widely expected to have no effect.
The critics, including Dr. Robert Gallo of the Institute of Human Virology in Baltimore, who helped discover the AIDS virus, signed a letter accusing the U.S. government of wasting more than $100 million by funding it.
But Thailand's health authorities and their U.S. partners at the National Institutes of Health and the Walter Reed Army Institute of Research pressed on with the trial, which involved 16,000 Thai volunteers.
"It was a tough decision. I am glad we made it," Dr. Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, who defied the criticism and continued the trial, told reporters.
The trial vaccine was made using two failed products -- Sanofi-Pasteur's ALVAC canary pox/HIV vaccine and AIDSVAX, made by a San Francisco company called VaxGen and now owned by the non-profit Global Solutions for Infectious Disease.
"This trial was controversial. In 2004, prominent U.S. scientists wrote a letter to Science magazine saying this shouldn't be done because the vaccines that had previously been tested were found wanting and didn't stimulate immunity of the right kind," said Donald Burke, dean of the University of Pittsburgh's Graduate School of Public Health.
"But given the importance of the AIDS epidemic, the decision was made to go forward regardless of these criticisms. It was a difficult choice, but a courageous choice," said Burke, who was head of AIDS research at Walter Reed before retiring in 1997.
Burke isolated the AIDS virus taken from a young HIV-infected Thai soldier in 1989, after Thai army doctors discovered an outbreak of HIV among young recruits in Chiang Mai, in northern Thailand. That virus sample went on to become one of the seed viruses in the experimental vaccine, Burke said.
"If I were to give any single group of people the credit, it would be the Ministry of Public Health of Thailand because it was a trial in Thai people," he added.
The $105 million trial was sponsored and paid for by the U.S. government and results showed it cut the risk of infection by 31.2 percent among 16,402 volunteers over three years.
"To their credit the Thais did a remarkable job on this," Dr. Eric Schoomaker, the Surgeon General of the U.S. Army, told reporters. "They did remarkable job of recruiting volunteers and conducting this trial almost flawlessly."
The surprising results mark another triumph for Thailand, which battled hard against a disease that threatened to spiral out of control some 20 years ago.
HIV prevalence among injecting drug users in Thailand was as high as 30-50 percent in 1991, and 33.2 percent among female sex workers in 1994, according to UNAIDS.
The Thai government responded in the early 1990s by launching a high-profile anti-AIDS campaign, including public education, improving treatment of sexually transmitted diseases, discouraging men from visiting prostitutes, promoting condom use and requiring sex workers to undergo regular health checks.
Infection rates fell and the exercise remains widely cited today as a model in disease prevention among health experts -- although numbers have shown signs of creeping up in the last few years among some high risk groups, such as gay and bisexual men.