Study: PEP is not
100% effective

Researchers from the Unviersity of California, San Francisco, report in the journal Clinical Infectious Diseases that postexposure prophylaxis to prevent HIV infection after nonoccupational exposure to the virus is not 100% effective. The researchers followed 702 HIV-negative adults who received a four-week regimen of antiretroviral drugs after being exposed to the virus through unprotected sex or shared needles. At 12 weeks after PEP was completed, seven of the study subjects--about 1%--had been infected with HIV. Of those seven, three had no other possible exposures to the virus during the follow-up period and were determined to have been infected despite PEP; it was unclear whether the other four were infected before or after PEP was administered.

The researchers note that anti-HIV drugs given after occupational exposures to HIV--usually through accidental "needle-stick" injuries to health care workers--also is not 100% effective in preventing HIV from taking hold in the body. Because occupational and nonoccupational PEP therapy is not a guarantee against HIV infection, primary HIV prevention practices remain essential, the study authors say. (Advocate.com)