Researchers from Boston University School of Medicine (BUSM) and Fenway Health have found that highly active antiretroviral therapy (HAART) does not completely suppress HIV in the semen of sexually active HIV-infected men who have sex with men (MSM). The findings, which currently appear on-line in AIDS, could indicate a potential transmission risk in MSM, who are highly susceptible to HIV infection.
Approximately 33.3 million people worldwide are living with HIV/AIDS, and 1.8 million deaths and 2.6 million new infections occur annually. Unprotected intercourse is the most common route through which HIV-1 is transmitted, and semen of HIV-infected men is an important source of HIV. Whereas the HIV/AIDS epidemic in Sub-Saharan Africa is generalized with approximately equal percentages of infections occurring in men and women, the epidemic in the United States and many other developed countries is concentrated in men who have sex with men. HAART, which is the primary treatment for HIV/AIDS, consists of a combination of potent anti-HIV drugs, which generally suppresses HIV levels in blood and semen, and HIV transmission to sex partners. However, sexually active MSM have a high prevalence of sexually transmitted infections which are a risk factor for HIV transmission.
To determine what percentage of sexually active HIV-infected MSM on HAART have HIV in their semen, the research team, headed by Deborah Anderson, MD, professor of obstetrics and gynecology at BUSM, recruited 101 men from Fenway health, Boston. They measured levels of HIV in blood and semen, and examined the relationship between HIV in semen and other clinical, behavioral and biological variables.
Eighteen percent of the men had HIV in blood despite being on HAART, and half of these men also had HIV in semen. “It has been shown before that HIV levels in peripheral blood are an important predictor of seminal HIV,” explained lead author Joseph Politch, PhD, research associate professor in obstetrics and gynecology at BUSM.
Highly Active Anti-Retroviral Therapy (HAART) consists of 3 or more highly potent anti-HIV drugs, commonly reverse transcriptase inhibitors and protease inhibitors.
The principle that lies behind HAART is that a single drug therapy may be successful for a while, but because HIV changes to avoid detection, drug-resistant strains will often arise in the patient. (This happens through a kind of evolution by natural selection - any new viruses which happen to be resistant to the drug will go on to multiply, while the others are stopped.) The chances of a HIV genome mutating such that it can resist three separate drug treatments at once, however, is so small that the pressure of this therapy prevents the emergence of resistant strains.
Of the 83 men with undetectable HIV in blood plasma, 25 percent had HIV in their semen. Detection of HIV in semen was strongly associated with high-risk (unprotected) sex behavior, sexually transmitted infections and genital inflammation.
“Our study provides evidence that genital infections and inflammation are common in HIV-infected MSM that engage in unprotected intercourse, and that these factors can promote HIV in the genital tract of men on suppressive HAART therapy even when HIV is not detectable in blood,” said Politch.
If you are diagnosed with HIV infection during the initial symptoms of early HIV (acute retroviral syndrome), discuss the use of highly active antiretroviral therapy (HAART) with your doctor. Information about treatment of early HIV from clinical trials suggests that treatment of early HIV with antiretroviral medicines have long-term benefits.
HAART medicines that are most often used to treat HIV infection include:
Nucleoside/nucleotide reverse transcriptase inhibitors, such as tenofovir, emtricitabine, and abacavir. These medicines are often combined with other medicines for best results.
Nonnucleoside reverse transcriptase inhibitors (NNRTIs), such as efavirenz, nevirapine, or etravirine.
Protease inhibitors (PIs), such as atazanavir, ritonavir, or darunavir.
Fusion and entry inhibitors, such as enfuvirtide and maraviroc.
Integrase inhibitors, such as raltegravir.
The U.S. National Institutes of Health recommends one of the following programs for people who begin treatment for HIV:
Efavirenz + tenofovir + emtricitabine
Ritonavir-boosted atazanavir + tenofovir + emtricitabine
Ritonavir-boosted darunavir + tenofovir + emtricitabine
Raltegravir + tenofovir + emtricitabine
The decision whether to start HAART before your health starts to decline is complicated. Consider the potential benefits and risks of early treatment and discuss all the issues with your doctor before starting HAART.
Because MSM are more vulnerable to HIV infection than heterosexual men, this information has potential clinical significance for the HIV epidemic in MSM. “Men who have sex with men who are at risk for transmitting HIV may believe that they have a low risk based on incorrect assumptions that HAART eliminates HIV from semen. Until more information on transmission risk in MSM is available, it would be prudent for sexually active HIV-infected MSM to use condoms and other risk-reduction strategies throughout all stages of HIV disease, regardless of HIV treatment status, and to promote the aggressive diagnosis and treatment of STIs,” Politch said. Kenneth Mayer, MD, Director of Research at Fenway Health and a co-investigator on the study added: “We would like to extend this research to study the effects of newer HAART regimens, since newer agents may have different effects on HIV suppression in different compartments in the body, which may have implications for HIV prevention.”
Boston University Medical Center