(CBS/AP) Two studies reported HIV pills could stop the spread of the disease in straight couples. Now, AIDS experts around the world are reacting with excitement over the groundbreaking findings.
"This is really a game changer," said Dr. Jared Baeten, a University of Washington researcher who led one of the studies.
Researchers announced Wednesday the results from two studies that showed the Gilead-manufactured HIV pills, Truvada and Viread, prevented disease transmission in heterosexual men and women.
"What a great day this truly is for HIV prevention," study researcher Dr. Michael C. Thigpen, epidemiologist for the Centers for Disease Control and Prevention, told WebMD. "Just a few years ago, we had very few tools to prevent infection."
For the first study, CDC researchers looked at 1,200 men and women in Botswana, half of which were given Truvada, while the other half took a placebo pill. Four people taking Truvada became infected with HIV, compared to 19 on the dummy pill - a 78 percent risk reduction for transmission.
The second study looked at more than 4,700 straight couples in Kenya and Uganda, where one partner had HIV and the other did not. The uninfected were given a placebo, Truvada pills, or another Gilead treatment, Viread. The researchers found 13 HIV infections in the group that took Truvada, 18 in those on Viread, and 47 among placebo-pill-takers. The HIV drugs reduced the risk of HIV infection by 62 percent and 73 percent, respectively.
"This is an extremely exciting day for HIV prevention," Dr. Kevin Fenton, director of AIDS prevention at the CDC told The New York Times.
"These studies could help us to reach the tipping point in the HIV epidemic," added Michael Sidibe, executive director of the United Nation's AIDS program.
At the same time, national and international health officials said it's unclear how these drugs will be used for prevention. How many people would take a pill each day to cut HIV infection risks? Would people become more sexually reckless?
Drug supply poses another problem. In Africa, 6.6 million people take AIDS drugs, but 9 million people who are eligible for the treatment are on a waiting list, according to the World Health Organization. In the U.S., state assistance programs also have long waiting lists for AIDS medication.
"Countries need to identify which populations could benefit the fastest and at the lowest cost," said Cate Hankins, chief scientific adviser at the United Nations' AIDS agency.
Despite the logistical issues, health officials remain hopeful.
"These studies could have enormous impact in preventing heterosexual transmission," said Dr. Margaret Chan, Director-General of the WHO. "WHO will be working with countries to use the new findings to protect more men and women from HIV infection."