Amsterdam study suggests PEP blocks virtually all HIV infections

A new study by researchers in Amsterdam shows that virtually all adults given anti-HIV drugs to prevent HIV infection after possibly being exposed to the virus are able to remain free of HIV, AIDSmap.com reports. All but one of the study subjects given a monthlong course of antiretroviral drugs remained HIV-negative six months after completing postexposure prophylaxis. The only man who seroconverted reported engaging in unprotected sex and again exposing himself to the virus after finishing a course of anti-HIV drugs, the researchers report in the April 9 edition of the British Medical Journal. The study tracked 225 people who were given anti-HIV drugs to ward off HIV infection, 53 of whom had been exposed to the virus through unprotected sex. In addition to antiretroviral drugs, all study subjects were given risk-reduction counseling to avoid future exposures to the virus. All of the study subjects remained free of HIV infection three months after PEP, but at the six-month mark, one man had seroconverted. He told researchers he had engaged in unprotected sex after completing his drug regimen, thereby reexposing himself to the virus. None of the study subjects developed hepatitis B or C. Follow-up interviews also showed that the availability of HIV postexposure prophylaxis did not lead the study subjects to engage more frequently in unprotected sex, the researchers report. Postexposure prophylaxis can prevent HIV infection if started within 72 hours of exposure to HIV, AIDS experts say, with the best results seen among those who begin the anti-HIV drugs as early as possible in that three-day window.