CDC Issues Guidelines for Use of Anti-HIV Drugs After HIV Exposure Through Sex, Injection Drug Use or Other High Risk Behaviors or Circumstances

What is NPEP? How Effective is NPEP? Who Would Benefit from NPEP? Who Would Not Benefit from NPEP? Limitations of NPEP Which Antiretroviral Treatments Are Recommended for NPEP? Importance of Risk Reduction Counseling Next Steps in HIV Prevention

For the first time, the US Centers for Disease Control and Prevention (CDC) has issued national guidelines for the use of anti-HIV therapy by individuals exposed to HIV in non-occupational settings, such as through sexual intercouse or injection drug use. This approach is called non-occupational post exposure prophylaxis (NPEP).

The 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. The sooner treatment is started, the more likely it is to interrupt HIV transmission. The treatment recommendation is for a combination of three anti-HIV drugs, which are taken for 28 days. Information on the treatment options should be drawn from the US Public Health Service Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents.

Dated January 21, 2005, the complete text of the NPEP guidelines is available online at www.cdc.gov/mmwr/mmwr_rr.html. Following is the CDC announcement on these new guidelines:

Nationwide, an estimated 40,000 new HIV infections occur every year, and there is concern that infections may be rising in some populations.  HIV prevention options that can help uninfected individuals stay negative are urgently needed.  In order to help provide an important safety net to reduce the risk of HIV infection, the U.S. government has issued national guidelines on the use of post-exposure antiretroviral treatment for people exposed through sexual intercourse, sexual assault, injection drug use, bite wounds or accidents. 

Post-exposure prophylaxis (PEP) with antiretroviral drugs has been recommended since 1996 for health care workers exposed to HIV through needle stick injuries and other occupational accidents.  NPEP represents an expansion of that strategy and, if used appropriately with other prevention methods, could be an important prevention alternative.  However, NPEP is not a substitute for abstinence, mutual monogamy, consistent and correct condom use, use of sterile needles and syringes to inject drugs and other behaviors that can help avoid HIV exposure in the first place. 

The national NPEP guidelines were developed by the U.S. Centers for Disease Control and Prevention (CDC), the Food and Drug Administration, the Health Resources and Services Administration and the National Institutes of Health.

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 needle sticks) – 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 specialized 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.  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. 


How Effective is NPEP?      Top

A growing body of data from human and animal studies, as well as findings from case studies and public health registries in locations where NPEP has been used, suggests that antiretroviral drug regimens can significantly reduce the risk of HIV transmission:

*Post-exposure prophylaxis has been associated with an 80 percent reduction in the risk of HIV infection among health care workers exposed to HIV on the job (e.g., through needle sticks).

*Providing antiretrovirals to HIV-infected women during labor and delivery, and to their newborns immediately following birth, has been shown to cut the risk of mother-to-child transmission by about 50 percent.

*In several national registries, few seroconversions have been noted among HIV-exposed patients treated with NPEP, including among 1000 reports in the United States’ registry.

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.

Who Would Not Benefit from NPEP?      Top

NPEP is not recommended for individuals whose HIV exposure risk is negligible, or for those who seek care more than 72 hours after suspected exposure.  NPEP is also not recommended for people whose behaviors result in frequent, recurrent exposures to HIV, such as those who have HIV-infected sex partners and rarely use condoms, or injection drugs users who often share equipment.  These individuals would require sequential or near-continuous courses of NPEP, which are not recommended.  Individuals at ongoing risk for HIV should instead be referred to intensive risk-reduction interventions.

NPEP should be used only for infrequent exposures and is not a substitute for risk-reduction behaviors.  Post-exposure prophylaxis has not prevented all HIV infections in occupational and perinatal settings, and similarly NPEP does not completely eliminate the risk of HIV infection.  In addition, use of antiretroviral therapy is often associated with unpleasant side effects such as nausea and fatigue. 

More serious side effects, such as severe allergic reactions and lactic acid build-up with enlargement of the liver, while rare, have also been known to occur.  Adhering to the prescribed regimen is key to NPEP’s effectiveness, yet many patients may find it difficult to comply with a month-long regimen of multiple drugs.  For all of these reasons, NPEP should not be viewed as a first line defense against HIV infection or as a substitute for behaviors that reduce HIV exposure.  Furthermore, NPEP should always be used in combination with risk-reduction counseling.

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 (Viramune), 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 (Sustiva), 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. 

Risk-reduction counseling and intervention services are critical components of NPEP and should be provided to all at-risk individuals.  Data show that when coupled with intensive risk-reduction counseling, NPEP can help patients maintain long-term safer behaviors.  For example, studies conducted in San Francisco and Brazil found that gay and bisexual men who received NPEP and prevention counseling were less likely to have unprotected sex a year or more later than they were before receiving these services.

With or without NPEP, health care providers should provide risk reduction counseling to all individuals who seek NPEP.  Providers should help their patients identify ongoing risks for HIV, develop plans to help them avoid exposure to HIV, and promptly link them to other counseling and support services.

The impact of biomedical interventions such as NPEP will be determined by how effectively they are used in combination with proven prevention strategies.  CDC supports a full range of proven approaches to reduce HIV infections in the U.S., including abstinence, mutual monogamy with an uninfected partner, correct and consistent condom use, expanded access to voluntary HIV counseling and testing, risk-reduction counseling for people both HIV negative and positive, linkage to drug-use treatment programs, and screening and treatment of sexually transmitted diseases, infections which can facilitate HIV transmission.

01/21/05

Source
US Centers for Disease Control and Prevention (CDC)

Reference
Antitiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States: Recommendations from the U.S. Department of Health and Human Services.  Morbidity and Mortality Weekly Report. Vol. 54 / No. RR—2. January 21, 2005.

www.cdc.gov/mmwr