CHAPEL HILL — A multinational study headed by a UNC-Chapel Hill researcher has led to a discovery that could help slow the spread of HIV.
Early treatment of heterosexual HIV patients with antiretroviral drugs sharply reduces the chances they will transmit the virus, according to results of the nine-nation study released Thursday.
HIV is the virus that causes AIDS. The $73 million study found that people with HIV are 96 percent less likely to spread it to a partner if they're placed on the regimen of drugs sooner than normal, a startling result that triggered international media coverage.
Dr. Myron Cohen, a professor of medicine, microbiology and immunology, and public health at UNC and director of the UNC Institute for Global Health and Infectious Diseases, is the principal investigator of the study, which he designed and organized.
Cohen said Thursday that he was elated by the results and overwhelmed by the attention they were getting. He is widely recognized as an international authority on the transmission and prevention of HIV/AIDS, and has spent more than two decades building a team at the university to study those topics.
Cohen announced the findings in a morning media telephone conference with an official from the National Institutes of Health, which paid for the study. Then he spent much of the rest of the day on the phone with journalists from the BBC, NBC, CBS, the Wall Street Journal, the New York Times and the Washington Post.
The study began in 2005 and had been expected to last until 2015. But the results were so profound that an independent monitoring board recommended that researchers release their findings early and tell the study participants.
"That was April 28, and I was just gobsmacked by the fact that we had essentially proven the hypothesis," Cohen said.
Couples around the world
The researchers then went to all 13 study sites to start spreading the word, he said. They explained the findings to ministers of health in all nine countries and began preparing the data for release years before they had expected.
The study involved 1,763 couples at sites in Botswana, Brazil, India, Kenya, Malawi, South Africa, Thailand, the United States and Zimbabwe. Each couple comprised one partner who had HIV but still had a relatively healthy immune system, and one partner who was not infected. The couples were randomly assigned to one of two groups.
In one group, the partners with HIV were immediately placed on the drug regimen. In the other, the drugs were withheld unless their immune systems weakened to a certain point, but were still above the range recommended by the World Health Organization for beginning the use of the drugs.
In 28 cases one of the previously uninfected subjects contracted HIV from his or her partner, all but one of them among the group in which use of the drugs was delayed.
UNC-Chapel Hill not only led the overall study, but it also operated one of the study sites, enrolling 251 couples at UNC Project-Malawi, the university's research, care and training center in Lilongwe.
The university has been conducting HIV research in Malawi since 1989.
Among those in the study, 97 percent were heterosexual couples. Because so few homosexual couples were enrolled, the study results can't be extrapolated to them, Dr. Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, said Thursday.
Participants given care
All the participants were provided with health care, HIV testing, and counseling on safe sex and condoms.
It's not clear to what degree they used the condoms, though they self-reported high rates of use, Cohen said. Those with HIV in the deferred treatment group are now being offered the drugs. It's likely that both groups benefited from the study's focus on safe sex, he said.
The study had been expected to continue until 2015. The researchers will continue to gather data for at least another year, Cohen said, but it's unclear what will happen long-term until everyone involved, from the researchers to the drug companies and patients, has a chance to talk through the issues.
Antiviral drugs have side effects and can be costly, and doctors often wait until a patient's immune system weakens to a certain point before recommending them.
The study was aimed partly at determining whether early use of the drugs could reduce transmission, and partly at examining the effects of the earlier treatment on those already infected.
At least one effect on those already infected was found: There were three cases of tuberculosis among those in the group that got the drugs early, and 17 among those who did not.
The data collected through the study are complex and are expected to yield findings beyond those announced Thursday, Cohen said.
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