Medical News

Most MSM Who Transmit Drug-Resistant HIV Aren't on Treatment, Swiss Study Reports

November 22, 2013

This article was reported by Science Daily.

An article from Science Daily reported on a study that drug-resistant HIV is mostly spread by people who are not being treated. Researchers led by Roger Kouyos and Huldrych Günthard at Zurich University Hospital used data from the Swiss HIV Cohort Study supported by the Swiss National Science Foundation. According to the Swiss HIV Cohort Study, one in every 10 newly infected individuals in Switzerland had viruses that were resistant to one of the three classes of drugs used to treat the disease.

The researchers conducted a molecular epidemiological analysis of 1,674 male carriers of HIV who had sex with other men. They found resistant viruses in 140 patients. The researchers then traced the transmission chains of these viruses based on patients' estimated infection dates and genetic relatedness of the viruses. Findings indicated that the majority of transmission chains began in HIV carriers who were not in treatment at the time the viruses were transmitted. Günthard stated that the researchers were surprised to find that the resistant viruses were circulated by untreated individuals. He explained that they had assumed that the resistant viruses were from patients for whom treatment had failed, as resistances were produced while treatment was ongoing.

The researchers concluded that preventing resistant strains depends on treating as well as preventing transmission by untreated individuals. This means that prevention and early detection of new infections are critical. Günthard noted that the HIV test required the patient's permission, and many doctors are reluctant to discuss a patient's sexuality openly with them, hence infections are not discovered until much later. With treatment, AIDS is no longer considered deadly, but there is much to be done in the fight against HIV/AIDS.

The full report, "Treatment-Naive Individuals Are the Major Source of Transmitted HIV-1 Drug Resistance in Men Who Have Sex With Men in the Swiss HIV Cohort Study," was published online in the journal Clinical Infectious Diseases (2013; doi:10.1093/cid/cit694).

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This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.

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