Occupational Postexposure Prophylaxis

July 2006

Chapter Contents

Background

Subjective

Assessment

Plan

Patient Education

References

Table 1. Recommended HIV Postexposure Prophylaxis after Percutaneous Injuries

Table 2. Recommended HIV Postexposure Prophylaxis after Mucous Membrane Exposures and Nonintact Skin Exposures*

Table 3. Antiretroviral Options for Occupational Postexposure Prophylaxis of HIV Infection

Background

Health care workers (HCWs) and other employees in medical, public safety, sanitation, and laboratory settings are at risk of occupational exposure to HIV. Although avoiding exposure to HIV is the only reliable way of preventing HIV infection, postexposure prophylaxis (PEP), defined as antiretroviral (ARV) therapy initiated soon after exposure to HIV, has been highly effective in preventing HIV infection in exposed HCWs.

This chapter examines the general issues involved with PEP in occupational settings. The information is based on the U.S. Public Health Service (USPHS) guidelines for PEP (see "References" below). For information on PEP for nonoccupational HIV exposures (such as sexual exposure), see chapter Nonoccupational Postexposure Prophylaxis . Note that other bloodborne pathogens, particularly hepatitis B virus (HBV) and hepatitis C virus (HCV), also may be transmitted through occupational exposure; it is important to consider these potential infections when assessing occupational exposures. For information on the management of occupational exposures to HBV and HCV, refer to the 2001 USPHS PEP guidelines on (see " References " below). In addition, the National Clinicians' Post-Exposure Prophylaxis Hotline (PEPline) is available 24 hours a day for telephone consultation at 888-HIV-4911 (888-448-4911).

The risk of HIV infection after exposure depends on several factors that are related to the exposure itself and to the source patient (see below). Before deciding whether to recommend PEP and what PEP regimen to recommend, the clinician must assess the risk of HIV infection from the particular exposure, as well as other factors such as the exposed worker's willingness and ability to take ARV medications. After this assessment, the clinician and the exposed worker must weigh the possible benefit of PEP (in relation to the risk of HIV transmission from the injury) against the potential toxicity of the regimen. HCWs who are pregnant at the time of their exposure also must weigh the risk of fetal exposure to HIV against the potential teratogenic and other risks of the ARV drugs. The efficacy of PEP is related to the specific PEP regimen, the timing of PEP, and the exposed worker's adherence to the PEP regimen. PEP should be initiated within 72 hours of the exposure, but is more likely to be effective when it is initiated within hours of the exposure. The optimal duration of PEP is not known; studies support treatment for 28 days.

In the work setting, HIV infection may occur through percutaneous injuries (eg, needlesticks) or mucocutaneous exposures (eg, mucous membrane or nonintact skin exposure to blood or other infectious body fluids). The risk of HIV seroconversion after occupational exposure is best described for needlestick injuries: 0.3%, on average after a needlestick with an HIV-contaminated hollow-bore needle. The risk varies depending on the specific incident. In general, exposures that involve prolonged contact with larger volumes of infectious body fluids, or higher HIV RNA levels in the blood or fluid, convey a higher risk of HIV transmission. In a retrospective case-control study of HCWs with percutaneous exposure to HIV, the following exposure and source patient factors were associated with an increased risk of HIV transmission:

• Large-gauge (<18-gauge) hollow-bore needle
• Deep injury
• Visible blood on the device
• Procedure with needle in a blood vessel
• Terminal AIDS in the source patient

Compared with percutaneous injury, mucocutaneous exposure of infectious body fluids to mucous membranes (eg, eye or mouth) or to skin with an obvious impairment of integrity (eg, abrasion or wound) typically involves a lower risk of HIV transmission. However, mucocutaneous exposures that involve large volumes of blood or other infectious fluid from an HIV-infected patient with a high HIV RNA level may be significant.

S: Subjective

The HCW reports possible exposure to HIV through a needlestick injury or mucocutaneous exposure.

Ideally, the HCW immediately decontaminated the injured or exposed skin with soap and water, or flushed the exposed mucous membranes with copious amounts of water or saline. The HCW should report the exposure immediately to the appropriate authorities in his or her health care institution (eg, the institution's needlestick hotline).

Take a thorough history of the specific exposure, including the type of exposure, the type and amount of body fluid involved, the point of entry or exposure, the time it occurred, the HIV status of the source patient (if known), and HIV risk factors of the source patient (if HIV status is not known).

A: Assessment

Assess potential exposure to HIV (as well as HBV and HCV). The HIV status of the source and the characteristics of the exposure should be assessed to estimate the risk of HIV infection. The decision about whether to offer PEP should be based on the estimated risk of HIV exposure. See Table 1 (percutaneous exposures) and Table 2 (mucocutaneous exposures) for recommendations about PEP.

P: Plan

Laboratory Testing

Provide pretest counseling and perform a baseline HIV antibody test. Test for other infections transmitted through occupational exposure, particularly hepatitis B (HBV surface antigen, surface antibody, core antibody), and hepatitis C (HCV antibody). Obtain complete blood count (CBC), chemistry panel, and liver function tests (LFTs) at baseline, before treatment with ARV medications. For women who may be pregnant, perform a pregnancy test.

Treatment

Consult Table 1 or Table 2 to determine whether the worker should be offered PEP medications. For occupational exposures to infectious body fluids from an HIV-infected source patient, the USPHS guidelines state that PEP should be recommended or considered, depending on the assessed risk. The assessed risk also helps to determine whether a "basic" 2-drug regimen or "expanded" ≥3-drug regimen should be selected. Other considerations in choosing the medications for a PEP regimen include:

• The likelihood that the source patient's virus is resistant to ARV medication(s)
• Possible drug toxicities for the exposed HCW
• Drug-drug interactions with other medications the HCW may be taking

If the HCW is a candidate for PEP, counsel him or her about the potential risks and benefits of PEP. If the worker elects to start therapy, consider potential regimens (Table 3). Select a regimen that is likely to be effective but tolerable; consider the potential adverse effects of ARVs. Note that certain ARV agents, including nevirapine, should not be used for PEP. Efavirenz should be avoided in pregnant women.

If the HIV status of the source patient is unknown, a rapid HIV test may help in determining the need for PEP (see chapter Rapid Testing ). Although a positive rapid test requires confirmation before the individual is diagnosed as HIV infected, for the purposes of PEP, it should be considered a true positive until proven otherwise, and the exposed worker should be counseled accordingly. If, upon further testing, the source patient is determined to be HIV uninfected, PEP can be discontinued. A negative rapid test is considered reliable unless the source reports recent high-risk HIV exposure or symptoms of primary HIV (see chapter Primary HIV Infection ). If a rapid test is not available, PEP is considered "generally not warranted" for exposures involving source patients whose HIV status is unknown. However, PEP can be considered if the source patient has risk factors for HIV infection. PEP should not be delayed (beyond 1-2 hours) while awaiting information about the source patient. PEP is not recommended for exposures to HIV-seronegative source patients.

If the source patient is known or suspected to have infection with HIV that is resistant to ARV medications, seek expert consultation in selecting an appropriate PEP regimen. However, PEP should not be delayed while consultation is obtained.

Additional alternative ARVs are included in the USPHS guidelines, but certain ARVs are not recommended for PEP, including abacavir, delavirdine, nevirapine, and the combination of didanosine + stavudine. Refer to the appendix in the updated USPHS guidelines for a more complete discussion of the dosing, advantages, and disadvantages of the various ARV agents available for PEP.

Begin ARV prophylaxis as soon as possible after the exposure, but always within 72 hours. Treatment should be continued for 28 days.

Provide counseling about the efficacy of PEP, including the importance of protection against future HIV exposures, timely initiation of PEP medications, and adherence to these medications for 28 days. Counsel exposed workers to use latex barriers with their sexual partners until HIV infection has been ruled out.

Follow-Up

Exposed workers should be evaluated at 1 week for review of all test results. For patients taking PEP, adherence assessment and evaluation of any side effects also should be included. At 2 weeks, blood testing (eg, CBC, LFTs) should be done for patients on a 28-day PEP regimen to monitor for PEP toxicity, as indicated by the particular ARV regimen. PEP is discontinued at 4 weeks, and generally no laboratory studies should be repeated unless there is a need to recheck an abnormal result. Follow-up HIV antibody testing should be done at 6 weeks, 3 months, and 6 months after the exposure. In addition to health-education counseling, some patients may need emotional support during their follow-up visits.

Symptoms of primary HIV infection such as fever, rash, and lymphadenopathy (see chapter Primary HIV Infection ) may occur in HCWs who have been infected with HIV through occupational exposure. Every exposed HCW should be counseled about the symptoms of primary HIV infection and instructed to return for reevaluation as soon as possible if symptoms develop. If symptoms consistent with primary HIV appear within 4-6 weeks after an occupational exposure, the HCW should be evaluated immediately. If the worker is found to be infected with HIV, he or she should be referred immediately to an HIV specialist for further evaluation and care.

Expert Consultation

For consultation on the treatment of occupational exposures to HIV and other bloodborne pathogens, the clinician managing the exposed patient can call the National Clinicians' Post-Exposure Prophylaxis Hotline (PEPline) at 888-HIV-4911 (888-448-4911). This service is available 24 hours a day, at no charge (additional information on the Internet is available at http://www.ucsf.edu/hivcntr ). PEPline support may be especially useful in challenging situations, such as when drug-resistant HIV strains are suspected or the HCW is pregnant.

Prophylaxis against HBV and HCV

Prophylaxis against hepatitis B is recommended for patients with potential exposure to HBV who have not been vaccinated against HBV. Give hepatitis B immune globulin (HBIG) as a 0.06-mL/kg intramuscular injection and initiate the vaccination series. For patients who received the vaccine series but did not develop protective antibody (HBV surface antibody positive), give HBIG at the time of the postexposure workup and repeat in 1 month. For patients with immunity to hepatitis B, no treatment is indicated.

For hepatitis C, no recommended prophylactic treatments are available. After potential exposure, conduct a baseline HCV antibody test. If the source is known to have HCV infection, consider alanine aminotransferase (ALT) and HCV viral load testing at 4-6 weeks. HCV antibody testing should be repeated at 4-6 months. If HCV seroconversion occurs (indicated by ALT elevation, detectable HCV viral load, or confirmed positive HCV antibody test), refer the patient to a hepatologist because early treatment of HCV may be indicated.

Addendum: Workplace Obligations

The health care institution has certain obligations to an exposed employee.* The institution should do the following:

• Evaluate the circumstances of the exposure, the type of fluid, and possible entry points.
• Evaluate the source patient.
• Perform baseline HIV antibody testing of the exposed worker, after appropriate pretest counseling.
• Counsel the exposed employee about the possible risks and benefits of PEP.
• Offer or recommend PEP as soon as possible after the exposure, preferably within the first several hours.
• Counsel the worker about avoiding secondary transmission to others (safer sex and other risk-reduction practices, as indicated).
• Support and maintain the confidentiality of the worker.
• For workers taking PEP, monitor for medication toxicity and adherence.
• Repeat HIV testing at 6 weeks, 3 months, and 6 months.
• Report the exposure as required by federal and state regulations (including Occupational Safety and Health Administration requirements).

* Legal issues vary from state to state. In many states, institutions and clinics have no obligation toward students or non-employees who have HIV exposures in their settings. In such situations, clinical supervisors or school or university officials often are the first contact for notification. However, anyone working in a health care setting should be familiar with the procedures and financial responsibility for HIV exposure management to avoid delays in HIV PEP treatment.

Patient Education

• Persons who have possible exposures to HIV in the work setting should contact the PEP service of their employer or a qualified medical provider as soon as possible after the exposure, or they should go to an emergency room. Although PEP may be effective if it is started within 72 hours of exposure, the sooner medications are initiated, the better the chance for preventing HIV transmission.
• PEP medications should be taken as directed for the full 28 days. Adherence to PEP medications is essential for successful teratment.
• PEP recipients should be advised to contact their providers if they experience uncomfortable side effects. Providers may prescribe medications to alleviate the side effects, or may prescribe different PEP medications.
• Until HIV infection has been ruled out, exposed workers should be advised to use latex barriers to prevent transmission of HIV to their sex partners.
• Exposed workers should be counseled about the symptoms of primary HIV infection and instructed to contact their care providers immediately if symptoms develop.

References

• Bassett IV, Freedberg KA, Walensky RP. Two drugs or three? Balancing efficacy, toxicity, and resistance in postexposure prophylaxis for occupational exposure to HIV . Clin Infect Dis. 2004 Aug 1;39(3):395-401.
• Cardo DM, Culver DH, Ciesielski CA, et al. A case-control study of HIV seroconversion in health care workers after percutaneous exposure . Centers for Disease Control and Prevention Needlestick Surveillance Group. N Engl J Med. 1997 Nov 20;337(21):1485-90.
• Centers for Disease Control and Prevention. Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to HBV, HCV, and HIV and Recommendations for Postexposure Prophylaxis . MMWR Recomm Rep 2001 Jun 29;50(RR11);1-42. Available online at aidsinfo.nih.gov/Guidelines/GuidelineDetail.aspx?GuidelineID=10. Accessed May 19, 2006.
• Centers for Disease Control and Prevention. Updated U.S. Public Health Service Guidelines for the Management of Occupational Exposures to HIV and Recommendations for Postexposure Prophylaxis . MMWR Recomm Rep. 2005 Sep 30; 54(RR09); 1-24. Available online at aidsinfo.nih.gov/Guidelines/GuidelineDetail.aspx?GuidelineID=10. Accessed May 19, 2006.
• Do AN, Ciesielski CA, Metler RP, et al. Occupationally acquired human immunodeficiency virus (HIV) infection: national case surveillance data during 20 years of the HIV epidemic in the United States . Infect Control Hosp Epidemiol. 2003 Feb;24(2):86-96.
• Gerberding JL. Clinical practice. Occupational exposure to HIV in health care settings . N Engl J Med. 2003 Feb 27;348(9):826-33.
• Puro V, Francisci D, Sighinolfi L, et al. Benefits of a rapid HIV test for evaluation of the source patient after occupational exposure of healthcare workers . J Hosp Infect. 2004 Jun;57(2):179-82.
• Wang SA, Panlilio AL, Doi PA, et al. Experience of healthcare workers taking postexposure prophylaxis after occupational HIV exposures: findings of the HIV Postexposure Prophylaxis Registry . Infect Control Hosp Epidemiol. 2000 Dec;21(12):780-5.