Preventing HIV After Exposure

CDC issues guidelines for rapid treatment to avoid sero-conversion

The federal Centers for Disease Control and Prevention (CDC) issued new guidelines on when and how to use anti-retroviral medications to prevent HIV infection in a person who has been exposed to the virus.

“While the most effective interventions remain those that prevent infections, if used appropriately… non-occupational post-exposure prophylaxis may provide a safety net to prevent new infections,” said Dr. Ronald O. Valdiserri, deputy director of the CDC’s National Center for HIV, STD and TB Prevention, during a January 20 conference call with reporters.

The guidelines call for administering a combination of three anti-HIV drugs within 72 hours “after HIV exposure to reduce the risk of infection to individuals exposed through sexual intercourse, sexual assault, injection drug use, bite wounds or accidents,” Valdiserri said. The treatment should continue for 28 days.

The “scientific rationale” is that, in the early days following HIV exposure, the “virus particles are only present in specialized cells in the part of the body where the exposure occurred,” Valdiserri said.

The drugs may stop the virus from moving into the body’s lymph system and then into the bloodstream.

“The sooner that treatment is started the more likely it is to interrupt infection,” Valdiserri said. “If HIV replication can be inhibited, the virus may not be able to establish itself.”

Valdiserri said that “a growing body of data from human and animal studies” supports the use of NPEP, as it is called.

Valdiserri and Dr. Lisa A. Grohskopf, an epidemiologist in CDC’s Division of HIV/AIDS Prevention who was on the conference call, stressed that NPEP was not a morning-after pill nor was it a substitute for traditional HIV prevention efforts.

“The new U.S. guidelines recommend NPEP only in limited circumstances,” Grohskopf said. “It is not recommended for individuals whose HIV risk is negligible or for those who seek treatment more than 72 hours after exposure… NPEP should be considered only in isolated circumstances and should be used only in conjunction with prevention services.”

Grohskopf said that those who have “frequent, recurrent exposures to HIV” are not candidates for NPEP. Such people should be referred to counseling, according to Grohskopf.

NPEP has been used for healthcare workers who were exposed to HIV, typically through needle stick accidents, since 1996.

While the guidelines are new, using NPEP for non-occupational exposures is not. The San Francisco health department has been offering NPEP since the mid-90s.

“I’ve certainly been advocating for a long time for protocols that don’t discriminate on the basis of how people get exposed,” said Dr. Joshua D. Bamberger, medical director for housing and urban health at the San Francisco Department of Public Health.

Bamberger oversaw a study that investigated the feasibility of offering the treatment. One issue was would NPEP lead to an increase in unsafe behaviors.

“That was the concern,” Bamberger said. “There were many articles written about that. Our data is pretty sound that offering medications does not increase risk.”

The Gay Men’s Health Crisis (GMHC) gets three to five hotline calls a week from across the nation about NPEP. They refer those callers to doctors and emergency rooms in New York and to other providers in Boston, Chicago, Atlanta, Los Angeles and San Francisco.

Bob Huff, editor of GMHC’s Treatment Issues, a monthly newsletter, said that NPEP was unlikely to become a widespread treatment.

“It may become more common, but it’s never going to be widely used because it is so difficult to use,” he said. “You have to start it within 72 hours and you have to continue it for 28 days.”

The treatment can cost between $600 to $1,000 and the side effects of the drugs can be unpleasant. And health care providers may not know it is an option.

“A key thing will be educating providers who haven’t heard about it before,” Huff said. “You can’t have people just dithering about it. You’ve got to start it right away.”