CDC releases detailed guidelines for PEP use

Agency focuses on nonoccupational exposure

While post-exposure prophylaxis (PEP) has been available to medical employees and first responders for years, public health officials have routinely dismissed the possibility of extending PEP to the general public, citing the inefficiency of its use even after potential exposure to HIV from rape.

This philosophy has changed with the recent release of guidelines for nonoccupational PEP (nPEP) by the CDC.

For the first time, the CDC has provided a detailed blueprint for how clinicians might recommend nPEP among patients who might have been exposed to HIV within the previous 72 hours.1

"It’s recommended only in limited circumstances," says Lisa A. Grohskopf, MD, MPH, epidemiologist in the CDC’s Division of HIV/ AIDS Prevention.

"It can be administered no more than 72 hours after exposure from a person known to be HIV infected, and it’s for those who have an occasional lapse, condom breakage or slippage, or who were assaulted," she says. "If the person’s HIV status is not known, then it can be used only on a case-by-case basis."

In introducing the guidelines in late January, CDC officials noted that far too many Americans are infected with HIV each year.

"African Americans are hardest hit with the burden of infection at a significantly higher rate than their counterparts in other ethnic and racial groups," says Ronald O. Valdiserri, MD, MPH, deputy director of the CDC’s National Center for HIV, STD, and TB Prevention.

"The severity of this epidemic dictates we utilize all available tools to reduce new infections," he says. "And if used appropriately with other prevention methods, nPEP may provide a safety net to prevent new infections."

The nPEP guidelines apply to nonoccupational exposures from sexual intercourse, sexual assault, drug use, bite wounds, and needlesticks outside of health care settings, Valdiserri says.

While it’s unethical to perform a randomized, placebo-controlled clinical trial of nPEP, data from animal transmission models suggest that it can be effective.1

Also, the short antiretroviral regimens used to reduce mother-to-child HIV transmission have been very successful and also suggest that a properly administered nPEP could prevent infection.1

Further, PEP studies involving needlestick injuries to health care workers found that prompt initiation of zidovudine was associated with an 81% decrease in risk of acquiring HIV.1

Feasibility studies of nPEP also have pointed to its potential success.1

"It’s important to note that nPEP is not for everyone," Grohskopf says. "It’s not recommended for individuals whose HIV exposure risk is negligible or for people who seek care after 72 hours after exposure."

It’s also not recommended for people whose behaviors put them at frequent risk for HIV exposure, she explains.

"People who are repeatedly exposed to HIV would need continuous courses of nPEP, which is not recommended," Grohskopf adds. "They need other interventions that are more likely to reduce their risk to HIV infection."

The guidelines recommend that baseline HIV testing with a rapid HIV test should be performed on all people seeking evaluation for nPEP and that nPEP initiation should not be delayed beyond 72 hours.1

Clinicians should evaluate patients who have had a potential nonoccupational exposure, assessing these factors, the guidelines say:

  • HIV status: The person seeking nPEP already could be infected with HIV.
  • Timing and frequency of exposure: If a patient requests nPEP more than 72 hours after exposure, the potential benefit may not outweigh the risks.
  • HIV status of source: When the source’s HIV status is unknown, the risk varies according to whether the source is part of a high-risk group.
  • Transmission risk from the exposure: Some types of transmission pose higher risk of infection, including blood transfusion, needle sharing by injection drug users, receptive anal intercourse, and percutaneous needlestick injuries.1

The CDC guidelines outline a 28-day course of antiretroviral therapy involving two or three drugs that are selected based on potential adherence, side effects, and cost.

"At this time, no evidence suggests any specific medications are optimal," Grohskopf says. "Regimens containing nevirapine should be avoided because the long-term use is associated with liver damage, and efavirenz may increase risk of birth defects."

Evidence from the nPEP feasibility study in San Francisco suggests the availability of nPEP may not lead to increases in risk behaviors, the guidelines note.

According to that study, 62% of participants reported a decrease in risk behavior over the next 12 months, 14% reported no change, and 14% reported an increase. Seventeen percent of participants requested a second course of nPEP during the year after the first course, which shows that some participants did not eliminate risk behaviors entirely.1

"Anyone who works in this field wants to make sure this intervention is understood and that people don’t see this as a morning-after pill," Valdiserri notes.

The use of nPEP is considered a safety net and not a substitute for other interventions that might reduce risk behaviors, Grohskopf says.

Each clinician should assess a risk-benefit ratio before using nPEP with a particular patient, adds Valdiserri.

"The clinician should know enough about the patient to understand if this incident truly is an episode, such as a gay man who very consistently practices safer sex and has a relapse of unsafe sex, and it’s an unusual event," he says. "The benefit of nPEP should outweigh the risks involved, and it’s a decision reached jointly between the health care provider and the client seeking nPEP."

Among the risks are side effects from the drugs and a cost of $600 to $1000 for the 28-day supply of antiretrovirals, Grohskopf notes.

"It’s unclear at this point to what degree nPEP would be covered by insurers," she says. "We hope that because there are federal guidelines, it will initiate a dialogue for what kind of coverage there might be."

Reference

1. Smith DK, Grohskopf LA, Black RJ, et al. Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States. MMWR 2005; 54(RR-2):1-20.