Thailand to Host ‘World’s Biggest’ HIV Vaccine Trial
The Thai government on Thursday announced that it will begin the "world's biggest" HIV vaccine trial in December, Agence France-Presse reports. The Thai government, in collaboration with other international groups including the U.S. Military HIV Research Program, the Royal Thai Army Medical Department and the U.S. National Institute of Allergy and Infectious Diseases, is set to enroll 16,000 healthy volunteers ages 20 to 30 for the Phase III trial, in which a combination of two vaccines developed by Aventis Pasteur and VaxGen will be administered in six injections over six months. Volunteers, who will be from the general population and not from a group of individuals at "high-risk" for acquiring HIV, will be instructed to take "normal precautions" against HIV regarding sexual behaviors and IV drug use. The five-year trial is expected to be the "last hurdle" before the HIV vaccine can be "administered freely," according to Supachai Rerks-ngarm, director of the program. "If the tests prove to be a success, Thai people will be the world's first" to have access to such a preventive vaccine, Public Health Minister Sudarat Keyuraphan said. Thailand is scheduled to host the next International AIDS conference in July 2004, Agence France-Presse reports. The conference will focus on the "growing" HIV/AIDS crisis in the Asia-Pacific region (Konglang, Agence France-Presse, 7/4).
Thai Program Aimed at Preventing Vertical HIV Transmission 'Highly Successful'
In related news, a nationwide Thai program aimed at preventing mother-to-child HIV transmission -- the first nationwide program of its kind in a developing country -- has been "highly successful," U.S. and Thai health officials reported in Barcelona on Saturday before the start of the conference, the New York Times reports. The Thai program, which began in October 2000 after successful pilot studies, offered zidovudine to the nation's HIV-positive pregnant women and their newborns. According to officials, 90% of Thai women who gave birth during the program's first year volunteered to be tested for HIV, and two-thirds of HIV-positive women opted to take zidovudine to prevent HIV transmission to their infants. In addition, 88% of infants born to HIV-positive mothers received zidovudine. Because it takes 18 months to determine if an infant has contracted HIV from the mother, health officials will not know for another year how many infants "escaped" HIV infection because of the program, according to the Times. However, Thai health officials estimate, because of the pilot study results, that the infection rate among the infants will be reduced by more than 50%. CDC epidemiologist Dr. R.J. Simonds, who worked on the Thai program from 1998 to 2001, said the program "provide[s] a beacon of hope" for expanding such a program to other developing nations (Altman, New York Times, 7/7).
Double Combination Therapy More Effective in Preventing HIV Vertical Transmission
A combination of nevirapine and zidovudine may be more effective in preventing mother-to-child HIV transmission than zidovudine by itself, according to preliminary results of an ongoing Thai study to be presented this week at the conference, the Associated Press reports. Thai researchers studied 1,500 HIV-positive women at 34 state hospitals. They administered zidovudine to one group of women at 34 weeks gestation and during childbirth and then administered it to their newborn infants as well. The researchers gave another group of women and infants both zidovudine and nevirapine in the same manner. Although zidovudine alone reduced HIV vertical transmission from 25% to 10%, the HIV vertical transmission rate in the group receiving the two-drug combination was less than 5%, according to preliminary results. "If the final results are as good as they appear to be, we will make it a national policy" to administer both zidovudine and nevirapine to HIV-positive women and their newborns, Siriporn Kanchana, deputy director-general of the Thai Department of Health, said (Noikorn, Associated Press, 7/5). According to Thailand's The Nation, the Phase III trial should be complete at the end of the year (Thailand The Nation, 7/5). Pregnant women make up approximately 1.5% of the nation's 900,000 HIV-positive residents, according to official estimates (Associated Press, 7/5).