BANGKOK— A clinical trial in Thailand has concluded a medication used to treat patients infected with HIV can also act as an effective prevention for all groups at high risk of acquiring the virus that causes AIDS. The United States-supported study showed the anti-retroviral drug Tenofovir cut the risk of HIV in half among injected drug users, the last high risk group to be tested.
Researchers from the United States and Thailand said a clinical trial of a medicine to prevent the spread of HIV showed a 49 percent reduction in risk among injected drug users.
The study of the antiretroviral Tenofovir began in 2005 and involved more than 2,400 men and women who inject drugs but were not infected with HIV.
Half were given Tenofovir and half a placebo. Both groups received counseling on drug abuse and HIV prevention. They were then monitored to see how many acquired the virus.
There were 33 HIV infections among those taking the placebo and 17 among those taking the anti-retroviral, a 49 percent reduction in risk.
Patients who took the medication most consistently had the highest levels of protection, reducing their risk of infection by 74 percent.
Dr. Michael Martin is chief of HIV research at the U.S. Center for Disease Control and Prevention's Southeast Asia office. He said while researchers continue to strive for a vaccine that would offer total protection, Tenofovir offers some of the most significant HIV prevention so far.
"We know that it can prevent HIV infection among people who inject drugs, among men who have sex with men, and among heterosexual couples. So, this is very good news for public health around the world," said Martin.
The study was conducted by the U.S. Centers for Disease Control and Prevention in collaboration with the Bangkok Metropolitan Administration and the Thailand Ministry of Public Health.
U.S. Ambassador to Thailand Kristie Kenney hailed the study as another step forward in U.S.-Thailand cooperation to eradicate HIV. "For twenty years Thailand and the United States have collaborated on HIV/AIDS, on the research, on the prevention, with the shared goal of 100 percent HIV/AIDS free generation," he explained. "And, I think today we're taking another important step in that direction."
Tenofovir was approved for use in the United States for HIV treatment in 2001 but was only recently proven effective for prevention.
A 2010 study in the U.S. showed, in combination with another drug, it reduced the risk of HIV infection among men who have sex with men by 44 percent. Testing in Botswana, Kenya, and Uganda demonstrated effectiveness among heterosexual couples and where one partner was infected with HIV.
Injected drug users were the last high risk group to be tested with Tenofovir in the Bangkok clinical trial.
Injected drug use accounts for up to 80 percent of new HIV infections in Eastern Europe and Central Asia, eight percent in the United States, and about ten percent worldwide.
Dr. Kachit Choopanya is principal investigator for the study. He said now that Tenofovir is proven effective for all high risk groups, it is up to governments to bring it into their health care systems. "And, we can save their life…I think everyone, not just Thailand, every country, should do this together," he stated.
An estimated 30 to 50 percent of injected drug users in Thailand are living with HIV.
Those who participated in the trial reported a decrease in injected drug use, sharing needles, and unprotected sex. Researchers said that indicates that counseling and education on HIV continues to be one of the most effective forms of prevention.