The US government today announced new public health guidelines on the use of non-occupational post-exposure prophylaxis (NPEP).
Introducing the new guidelines, the US Centers for Disease Control said: “New HIV prevention interventions are urgently needed for gay and bisexual men in the U.S. Data show that HIV/AIDS diagnoses among men who have sex with men (MSM) in 32 states are on the rise. And while most gay men take steps to reduce their HIV risk, condom breakage or occasional lapses in safer behaviour can still place them at risk for infection.”
“The severity of this epidemic dictates that we use all available to tools to prevent new infections,” said Dr Ronald Valdiserri, Deputy Director of CDC's National Center for HIV, STD and TB Prevention.
NPEP is the use of antiretroviral drugs immediately after a non-occupational exposure to HIV – either from sexual intercourse, sexual assault, injection drug use, bite wounds or accidents (e.g., unintentional needlesticks) – to prevent infection from taking hold in the body. A combination of three antiretroviral drugs is started within 72 hours of exposure and is taken daily for 28 days.
“For a short period of time following exposure to HIV, virus particles are present only in specialised cells in the part of the body where exposure occurred. If HIV replication can be inhibited during that window of exposure, the virus may not be able to establish a permanent infection,” Dr Valdiserri told a press briefing today. “Using antiretroviral drugs within hours of exposure may inactivate the HIV that is present and prevent it from migrating to the lymphatic system, replicating in cells there, and then spreading into the bloodstream and throughout the body. The sooner treatment is started, the more likely it is to interrupt HIV transmission.”
Post-exposure prophylaxis has been recommended for health care workers exposed to HIV through occupational accidents since 1996.
The U.S. government guidelines recommend NPEP only in limited circumstances – for people who seek treatment no more than 72 hours after a high-risk exposure from a person known to be HIV-infected.
People who would benefit from NPEP include HIV-negative individuals who occasionally lapse in safer sex or drug-use behavior, or experience condom breakage or slippage with a partner who is positive, and those who are exposed through sexual assault or accidents. If the HIV status of the source person is not known, use of NPEP should be considered on a case-by-case basis for people who seek care within 72 hours of suspected exposure. Clinicians should take into account the specific circumstances of the possible exposure and the likely risk of infection. If possible, the source person should be asked to take a rapid HIV test to determine if NPEP is appropriate.
Unlike UK guidelines, which make specific recommendations on drugs to use for PEP, the US guidelines say that any antiretroviral therapy combination approved by the U.S. Department of Health and Human Services may be used for NPEP. No specific antiretroviral medication or combination of medications is known to be optimal for use as NPEP. However, regimens containing the drug nevirapine, which has been associated with adverse reactions and liver damage, should be avoided. Women who are pregnant or of childbearing age should not receive regimens containing the drug efavirenz, which may increase the risk of birth defects. When available, the source person’s history of antiretroviral medication use and most recent viral load measurement should be considered when selecting antiretroviral medications for NPEP.
Developed by CDC, the Food and Drug Administration, the Health Resources and Services Administration and the National Institutes of Health, the new guidelines will be published in the January 21 issue of CDC's Morbidity and Mortality Weekly Report, and will be available at www.cdc.gov/mmwr.