Chapter 11
Postexposure Prophylaxis

Renslow Sherer, MD
Bruce D. Agins, MD, MPH
Caroline J. Teter, PA-C, MPH

Overview   TOP

What is postexposure prophylaxis (PEP)?

Postexposure prophylaxis (PEP) prevents or aborts transmission of HIV with rapid initiation of short-term antiretroviral therapy (ART) following occupational or nonoccupational exposure. PEP should be considered in all health care personnel (HCP) and non-HCP exposed to blood or potentially infectious body fluids via percutaneous, mucous membrane, and nonintact skin exposures, injection drug use, intentional or unintentional sexual exposures, and human bites. Hepatitis B infection may be prevented following administration of immune globulin and vaccination when indicated.

PEP policies should be instituted in all health care settings. The essential elements include:

• Written protocols for documenting and managing exposures
• Assessment, counseling, and intervention immediately after any exposure
• Rapid access to medications and/or immunization, if indicated

What do we know about the effectiveness of PEP for HIV?

Retrospective case-control studies support the efficacy of PEP for occupational exposure to HIV, and 4 factors are associated with increased transmission rates: 1) deep injury, 2) visible blood on device, 3) needle placement in artery or vein, and 4) late stage HIV disease in source (this risk factor was identified prior to viral load testing, thus high viral load is likely an independent risk factor). Evidence of the effectiveness of nonoccupational PEP comes from small observational human studies, extrapolation of data showing the interruption of maternal-infant transmission, and animal studies showing some degree of protection from genitally and intravenously acquired HIV. Even with optimal implementation, the degree of protection afforded by PEP is incomplete. Studies of PEP have demonstrated the greatest reduction in HIV transmission when antiretroviral medications are administered immediately after exposure to HIV-infected blood and body fluids. The efficacy of PEP is diminished after 36 hours and is minimal after 72 hours.

What do we know about the effectiveness of PEP for hepatitis B and C?

Hepatitis B transmission can be prevented through administration of immune globulin and hepatitis B vaccine. PEP for hepatitis C virus (HCV) has thus far proven to be ineffective.

What body fluids are infectious for HIV, HBV, HCV?

Blood is the most infectious body fluid. In the health care setting, cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids are all considered potentially infectious, although the only documented cases of occupational HIV infection have been with blood, body fluids with visible blood, or HIV viral cultures. Unless there is visible blood with the exposure, saliva, nasal discharge, tears, sweat, vomit, urine, and feces are not infectious. Semen and vaginal secretions are infectious for HIV, HBV, and HCV in the setting of nonoccupational exposure.

Interventions for PEP in Health Care Settings  TOP

What types of exposures merit consideration of PEP in health care personnel (HCP)?

HCP are at increased risk from percutaneous, mucous membrane, and nonintact skin exposures to bloodborne pathogens, including hepatitis B, hepatitis C, and HIV. The risk of transmission is dependent on many factors, including the type, amount, route, and severity of exposure, the infection status of the source, and the HBV, HCV, and HIV immunity of the exposed worker (see Tables 11-1 and 11-2).

An accurate history of the exposure is essential in determining the real risk of transmission. In studies, transmission of HIV by occupational exposure has an estimated 0.3% risk with percutaneous exposure and 0.09% with mucous membrane splash (Bell, 1997). The risk of infection for HBV (in individuals who have not been vaccinated to hepatitis B, or who were vaccine unresponsive) after percutaneous exposure is 37%-62% when the source is hepatitis B surface antigen (HbsAg) positive and hepatitis B e antigen (HBeAg) positive, and the risk of developing clinical hepatitis is 22%-31%. When the source is HbsAg positive and hepatitis B e antigen negative, the risk of HBV seroconversion is 1%-6%, and the risk of developing clinical hepatitis is 23%-37%. The risk of transmission is higher, ie 22%-31%, when the source has clinically evident hepatitis B hepatitis (Werner and Grady, 1982; CDC, 2001). Transmission of HCV through occupational exposure carries an average risk of 1.8%.

What are immediate actions and initial considerations in PEP following a possible occupational exposure?

First aid for the HCP is the first immediate action, followed by collection of information in order to assess the situation and make rapid decisions regarding appropriate treatment (see Tables 11-3, 11-4, and 11-5). Quick, expert action by the care provider is essential because the effectiveness of PEP is variable and depends on the inoculum, type of injury, potency of the PEP regimen, and speed with which treatment is started. The decision to prescribe medications, as well as medication administration, should be made within 4 hours of the exposure, and must be made within 72 hours, and preferably sooner because of studies suggesting that the efficacy of PEP is diminished after 36 hours. Even with optimal implementation, ie within the first 4 hours, the protection afforded by PEP is not 100%.

What counseling and education should you give the HCP?

The exposed HCP needs immediate counseling to assist in coping with the emotional stress of the exposure, and may require follow up care by a mental health professional. Psychological services should be available 24 hours a day, 7 days a week. A local crisis management team or an employee assistance program (EAP) may be effective ways to address this need.

The HCP should be told the relative risk of infection with HIV, HBV, and HCV following exposure, the effectiveness of PEP, and the risks and benefits of PEP. Exposed persons should be advised to return immediately if symptoms of acute HIV seroconversion occur, including fever, malaise, rash, swollen lymph nodes, fatigue or myalgias (most likely to occur 2-6 weeks after exposure).

Providers should advise exposed HCPs to prevent transmitting HIV to others, by means of the following measures, until the HCP has a negative HIV test 6 months after exposure:

• Refrain from donating blood, plasma, organs, tissue, or semen.
• Use barrier protection during sexual activity.
• If HCP is female, avoid pregnancy.
• If breast feeding, consider discontinuing, to avoid the risk of HIV transmission through breast milk.

If exposed to HBV, the HCP should follow infection control procedures that are in place at the institution.

Are there special considerations for PEP in dental settings?

Although the number of exposures is relatively high in dental settings, the risk of transmission is low and no different from other HCP settings. Factors that are associated with increased risk of transmission are failure to follow PEP protocols, failure to use puncture-proof containers, treating >20 patients per day, failure to use eye protection or masks, and male gender. For more information, see Suggested Resources.

Interventions for Nonoccupational PEP (NPEP)  TOP

What is the role of nPEP for nonoccupational exposure?

PEP for nonoccupational exposure to HIV (nPEP) is routinely being administered in cases of sexual assault in hospital emergency departments and is increasingly being made available during other cases of sexual exposure or injection drug use exposure and in non-hospital settings. This issue is particularly relevant in the care of HIV discordant couples. Research on risk of HIV transmission from a single nonoccupational exposure is relatively lacking compared with occupational exposures (see Table 11-6). A national registry has been developed to gather the data with which to develop a CDC recommendation for HIV PEP in the nonoccupational setting. Information about this registry can be found at http://www.hivpepregistry.org. In general, PEP for non-HCP is modeled after PEP interventions and procedures for HCP.

Source: Mayer KH, Anderson DJ. "Heterosexual HIV transmission."
Infect Agents Dis. 1995;4:273-284.

What needs to be evaluated for the possible administration of PEP in the nonoccupational setting?

Factors to be considered when considering PEP for nonoccupational exposure are similar to those for occupational exposure, including 1) HIV status of potentially exposed person (a rapid test can be done in 20 minutes), 2) timing (within 72 hours, with rare exception) and frequency of exposure (recurrent exposure would require ongoing PEP and suggests need for prevention counseling as the primary intervention), 3) HIV status of source (if unknown, PEP can be initiated while this is being assessed and discontinued if HIV infection of the source cannot be confirmed), 4) transmission risk of behavior (see Table 11-6), 5) presence of other sexually transmitted diseases, particularly genital ulcer disease (which can facilitate HIV transmission). Exposures to persons who have recently seroconverted may carry a higher risk of transmission because of high HIV viremia.

What is the role of PEP for discordant couples?

Discordant couples (couples in which one person is infected and the other is not) should be routinely educated about how to protect the noninfected person. Both partners should be made aware of the possible effectiveness of PEP in cases of intended or unintended exposures and the importance of early initiation of PEP if it is to be used. Repeated, frequent exposures should signal providers to exercise caution about administration of PEP, since PEP should not be a substitute for avoidance of high-risk behavior. Any request for PEP should prompt additional counseling and psychosocial support to enhance behaviors to prevent HIV infection.

What is the role of PEP following sexual assault?

Persons who have been sexually assaulted should be considered at risk for HIV and HBV, as well as other STDs. The decision to begin PEP should not be based on the perpetrator's likelihood of infectivity or delayed pending the test results of the source (unless immediately available). Pregnancy is an important consideration when considering PEP, and emergency contraception should be considered for women who have been sexually assaulted.

A survivor of sexual assault may have had multiple exposures. When considering PEP, the most recent exposure should be considered, and PEP should be initiated if the exposure took place within 72 hours before the patient arrived at the health care facility. As with any consideration for PEP, weighing the benefits of PEP versus the possibility of medication side effects, the importance of completing the 28-day regimen and adherence issues should all be considered.

The provider should be sensitive to the psychosocial needs of the person who was sexually assaulted; the patient may not be physically or emotionally able to weigh the pros and cons about beginning PEP. Therefore, it is important to follow up within 24 hours to either emphasize the importance of adherence or to continue the discussion about initiating PEP if is to occur within the 72-hour window.

See Suggested Resources for more information and resources in addressing issues of sexual assault.

What if the person who is exposed is a minor?

In cases involving minors, parental or guardian participation is extremely important, but parental or guardian consent for PEP may not be required. Nonetheless, in all cases, parental or guardian participation should continue to be sought in the emergency situation and during followup. State laws and hospital policy must be considered.

HIV PEP Treatment Recommendations  TOP

If PEP is found to be appropriate, what information does the exposed person need regarding treatment?

The exposed person must understand the risks and benefits of HIV PEP, potential medication toxicities and side effects, instructions on how and when to take the medication, and the importance of adherence to the regimen, including completing the course of 28 days. Women should understand pregnancy-associated risks, including perinatal transmission and teratogenicity. Breast-feeding should be discontinued until the woman receives an HIV-negative result 6 months after exposure.

What are HIV treatment recommendations and options for PEP?

Currently recommended regimens are shown in Tables 11-7, 11-8, and 11-9; however, these recommendations may be altered if the source patient has a history of ART or known viral resistance, is pregnant, breast-feeding, has hepatic or renal disease, or is taking certain medications. If viral resistance in the source patient is known or suspected, an HIV expert should be consulted prior to initiating HIV PEP medications.
Basic HIV PEP regimens include 2 NRTIs. These regimens are relatively simple, ie 1 or 2 pills twice a day, well tolerated, and of sufficient potency to meet the needs of PEP. However, they are substantially less potent than 3-drug regimens. As noted below, some experts, including the authors, believe that only 3-drug regimens should be used for PEP, particularly in the current era of greatly simplified and somewhat better tolerated 3-drug regimens.

⁸ For skin exposures, follow-up is indicated only if there is evidence of compromised skin integrity (e.g., dermatitis, abrasion, or open wound).

* HIV-Positive, Class 1 asymptomatic HIV infection or known low viral load (e.g., <1,500 RNA copies/mL). HIV-Positive, Class 2 - symptomatic HIV infection, AIDS, acute seroconversion, or known high viral load. If drug resistance is a concern, obtain expert consultation. Initiation of postexposure prophylaxis (PEP) should not be delayed pending expert consultation, and, because expert consultation alone cannot substitute for face-to-face counseling, resources should be available to provide immediate evaluation and follow-up care for all exposures.

+ Source of unknown HIV status (e.g., deceased source person with no samples available for HIV testing).

Ø Unknown source (e.g. splash from inappropriately disposed blood).

¶ Small volume (i.e., a few drops).

** The designation , "consider PEP," indicates that PEP is optional and should be based on an individualized decision between the exposed person and the treating clinician.

§ If PEP is offered and taken and the source is later determined to be HIV-negative, PEP should be discontinued.

† Large volume (i.e., major blood splash).

Source: 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 2001;50(RR11):25.

* HIV-Positive, Class 1 asymptomatic HIV infection or known low viral load (e.g., <1,500 RNA copies/mL). HIV-Positive, Class 2 - symptomatic HIV infection, AIDS, acute seroconversion, or known high viral load. If drug resistance is a concern, obtain expert consultation. Initiation of postexposure prophylaxis (PEP) should not be delayed pending expert consultation, and, because expert consultation alone cannot substitute for face-to-face counseling, resources should be available to provide immediate evaluation and follow-up care for all exposures.

+ Source of unknown HIV status (e.g., deceased source person with no samples available for HIV testing).

Ø Unknown source (e.g. a needle from a sharps disposal container).

¶ Less severe (e.g., solid needle and superficial injury).

** The designation , "consider PEP," indicates that PEP is optional and should be based on an individualized decision between the exposed person and the treating clinician.

§ If PEP is offered and taken and the source is later determined to be HIV-negative, PEP should be discontinued.

† More severe (e.g, large-bore hollow needle, deep puncture, visible blood on device, or needle used in patient's artery or vein.

Source: 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 2001;50(RR11):24

* NRTI: nucleoside or nucleoside reverse transcriptase inhibitor
** PI: protease inhibitor
# NTRTI: nucleotide reverse transcriptase inhibitor, i.e., tenofovir (TDF)
*** NNRTI: non-nucleoside reverse transcriptase inhibitors, i.e., efavirenz (EFV)

Three-drug regimens, comparable to highly active antiretroviral therapy (HAART) regimens used to treat HIV infection, are recommended for more severe exposures, which carry a higher risk of HIV transmission, or with exposures to sources with known HIV resistance mutations. The 3-drug regimens increase the risk of medication toxicity and may worsen adherence, all of which should be weighed when choosing an HIV PEP regimen. The majority of exposures in the past have resulted in the administration of 2 medications; 3-drug regimens should be chosen with the advice of an HIV expert. In accordance with the same principles that are used in treating HIV-positive persons; some experts believe that 3-drug PEP regimens should be the mainstay of PEP and that 2-drug regimens should be used only during extenuating circumstances such as an inability to tolerate a protease inhibitor (PI). For example, the New York State PEP Guidelines now recommend zidovudine and lamivudine (Combivir) plus tenofovir (two pills in the morning and one pill in the evening) as the standard PEP intervention. (http:\\www.hivguidelines.org)

Although the current data on PEP for nonoccupational HIV exposures are scant, treatment recommendations for occupational PEP can be generalized to nonoccupationally exposed persons. As in the case of PEP in HCP, nonjudgmental counseling directed towards the reduction of future exposures is an important part of PEP in nonHCP.

What are the side effects of HIV PEP?

Side effects of HIV PEP regimens are common and occur in 30%-50% of patients. Severe side effects occur in 5%-30% of patients and often require discontinuation. Common side effects include gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain; rash; fatigue; headache and dizziness; cytopenia; neuropathy; hepatitis; and many others. In reported series to date, over half of HCP in PEP programs fail to complete their 28-day regimens because of side effects. Regularly scheduled followup either in person or by phone has been shown to greatly improve adherence. Refer to other chapters for more detail on symptom management and metabolic complications with ART.

What medication toxicities should be monitored?

Regular laboratory evaluation for medication toxicity and seroconversion should be performed (see Table 11-5). A complete blood count and renal and hepatic function tests should be done before initiating PEP and repeated in 2 weeks. Continued monitoring is recommended for abnormal lab test results, and medication changes should be considered if abnormalities are severe. Specific monitoring parameters vary with the regimen; for example, glucose levels should be monitored if a PI is used. If the PI is indinavir (IDV) a urinalysis should also be checked to monitor for crystalluria and hematuria. Tenofovir (TDF) is well tolerated, but should be used with caution and careful monitoring in patients with compromised renal function (Refer to Drug Information Tables in the Pocket Guide for medication side effects.)
Two regimens deserve special consideration. Hepatotoxicity, Stevens-Johnson syndrome, and fatal hepatic necrosis have occurred in HCP treated with nevirapine (NVP) as part of their PEP regimen, and therefore its use is not recommended, given the variety of other options. Pregnant women treated with stavudine (d4T) and didanosine (ddI) were found to be at increased risk for fatal and non-fatal lactic acidosis, and therefore this combination is not recommended in the treatment of pregnant women. In addition, recent clinical trial data showed a higher rate of adverse effects with the combination of stavudine and didanosine in adults, and their use in combination is not recommended unless other alternatives are not available.

What are the treatment recommendations when the source patient is known to have specific HIV resistance mutations?

Resistance to HIV medications is an important consideration in the treatment of HIV-positive persons, and known resistance in the source patient should be a consideration when choosing an appropriate HIV PEP regimen. In addition, because of reported increases in resistance mutations in recently acquired HIV infection in several cities in the United States, resistance is increasingly a concern in untreated patients, and thus for PEP in exposures to unknown sources. HIV PEP failures attributed to exposure to resistant virus have been reported in the literature.

Unfortunately, resistance test results are often unavailable at the time of the consideration of PEP, and PEP should not be unduly delayed while this information is sought. A thorough drug, adherence, and HIV history from the source patient and consultation with an HIV expert is needed to make the optimal treatment recommendation.

When should expert consultation be sought?

Expert consultation is potentially valuable in many circumstances with PEP. As above, expert consultation is indicated in the setting of known or suspected drug resistance in the source in order to select drugs to which the patient's virus is likely to be susceptible. Other situations include:

• Delayed report of exposure, since the interval after which there is no benefit from PEP is undefined, in order to determine if PEP is still indicated
• Unknown status of the source, since the decision regarding the use of PEP should be individualized, based on the estimated likelihood of risk to the HCP, considering the severity of the exposure and the epidemiologic likelihood of HIV exposure
• Known or suspected pregnancy in the exposed person, in which case specific treatment recommendations may require modification
• Possible toxicity of the initial PEP regimen, in which case modification of the regimen and/or treatment of the adverse side effect may be considered
  

Hepatitis PEP Treatment Recommendations  TOP

What are the treatment recommendations and options for possible hepatitis B exposure?

HBIG and immunization against HBV following exposure are the most effective methods to prevent HBV transmission (see Table 11-10). PEP for HBV with multiple doses of HBIG has been shown to be 75%-95% effective. Pregnant women can safely receive both the HBV vaccination and HBIG. When considering PEP for HBV exposures, both the source patient's HbsAg status and the exposed person's vaccination status and antibody response should be considered. Both HBIG and the hepatitis B vaccine should be administered within 24 hours of exposure. Anti-HBs should be drawn 1-2 months after completion of the third vaccine, but it is unreliable if the exposed person has received HBIG within the past 3-4 months.

* Persons who have previously been infected with HBV are immune to reinfection and do not require postexposure prophylaxis.

+ Hepatitis B surface antigen.

§ Hepatitis B immune globulin; dose is 0.06 mL/kg intramuscularly.

¶ Hepatitis B vaccine.

** A responder is a person with adequate levels of serum antibody to HBsAg (ie, anti-HBs = 10mlU/mL).

Ø A nonresponder is a person with inadequate response to vaccination (ie, serum anti-HBs < 10mlU/mL).

† The option of giving one dose of HBIG and reinitiating the vaccine series is preferred for nonresponders who have not completed a second 3-dose vaccine series. For persons who have previously completed a second vaccine series but failed to respond, two doses of HBIG are preferred.

¶¶ Antibody to HBsAg.

Source: 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 2001;50(RR11):22.

What are the treatment recommendations and options for possible hepatitis C exposure?

There are no recommended prophylactic treatments after exposure to HCV blood or body fluids. Current data do not support treatment during acute HCV infection at this time; referral of an individual with recently acquired HCV to a specialist in HCV care is appropriate.

Following exposure, testing should be performed on the source for anti-HCV. If positive, the exposed person should be tested for anti-HCV and alanine aminotransferase (ALT) initially and in 4-6 months. HCV-RNA and ALT at 4-6 weeks are optional. All anti-HCV results should be confirmed by recombinant immunoblot assay; if positive an HCV RNA should be drawn. Drawing an HCV RNA at 4-6 weeks may be done for earlier diagnosis, but the person should be counseled that false-positives do occur. Current research supports early diagnosis of HCV as basis for the most effective management after exposure are known. Exposed persons should be counseled to refrain from donating blood, plasma, organs, tissue, or semen. Although the transmission risk by sexual activity is low, it is reasonable to recommend a barrier method until the results of testing 6 months after exposure are known. There are currently no recommendations to make any changes in breast-feeding, pregnancy, or professional activities. Mental health counseling should be offered as needed.

• The goals of PEP are to prevent or abort the transmission of HIV and hepatitis B virus (HBV) and to enable early diagnosis of hepatitis C virus (HCV).
• All exposed persons need followup within 24-48 hours depending on the pathogen.
• HIV PEP, if determined to be appropriate, should be provided preferably immediately, and definitely within 36 hours of exposure. PEP is NOT recommended for minor exposures. If the provider is inexperienced in using HIV medications or managing PEP patients, an HIV specialist should be consulted before initiating treatment.
• The risk of transmission of HBV is far greater than of HIV or HCV. All HCPs should be vaccinated against HBV. HBIG is highly effective in preventing transmission of HBV.
• There is currently no recommended PEP medication for HCV. If possible, the source should be tested for antiHCV, and if positive, the exposed person should be monitored.
• PEP should be available in all health care settings. PEP protocols should be developed, regularly updated, and included in regular employee training programs.
• PEP for nonoccupational exposure (nPEP) is modeled after PEP for occupational exposures. nPEP is routinely administered in cases of sexual assault in emergency departments, and is increasingly being made available for other cases of sexual exposure or injection drug use exposure in non-hospital settings.

References  TOP

Bell DM. "Occupational risk of human immunodeficiency virus infection in healthcare workers: an overview." Am J Med. 1997;102(suppl 5B):9-15.

Cardo DM, Culver DH, Ciesielski CA, et al. "A case-control study of HIV seroconversion in health care workers after percutaneous exposure." N Engl J Med. 1997;337:1485-1490.

Centers for Disease Control and Prevention. "Updated guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for postexposure prophylaxis." Public Health Service. MMWR. 2001:50(RR11):1-42.

Centers for Disease Control and Prevention. "Management of possible sexual, injecting-drug-use, or other nonoccupational exposure to HIV, including considerations related to antiretroviral therapy." Public Health Service Statement. MMWR. 1998; 47(RR-17):1-14.

Centers for Disease Control and Prevention. "Recommendations for the prevention and control of hepatitis C virus (HCV) infection and HCV-related chronic disease." MMWR. 1998; 47(RR-19):1-39.

Gerberding JL. "Occupational exposure to HIV in health care settings." N Engl J Med. 2003;348:826-833.

New York State Department of Health AIDS Institute. HIV PEP Guidelines. Accessed 1/04.

Mayer KH, Anderson DJ. "Heterosexual HIV transmission." Infect Agents Dis. 1995;4:273-284.

Stephenson J. "PEP talk: treating nonoccupational HIV exposure". JAMA. 2003;289:287-288.

Werner BG, Grady GF. "Accidental hepatitis-B-surface-antigen-positive inoculations: use of e antigen to estimate infectivity." Ann Intern Med. 1982;97:367-369.

Cases  TOP

1. An employee states that she has just punctured herself with a needle after drawing a patient's blood. The patient has already left the clinic and no one knows anything about his medical history. The employee completed the HBV vaccination series and is hepatitis B surface antibody (HBsAb) positive. During the investigation the HIV prevalence in this setting was found to be low.

Question: What is the risk of HIV transmission?

Answer:
The risk of HIV transmission after a puncture wound with a hollow-bore needle is 0.3%. It is important to remember that the risk of infection is higher when there is a large-volume exposure, a deep percutaneous injury, or an injury with a hollow-bore, blood-filled needle, or if the source has advanced HIV disease or has a high level of HIV viremia. The current CDC recommendations advise against HIV PEP when the source is unknown and in settings where the HIV prevalence is low.

Question: What counseling and followup should be recommended?

Answer:
Because of the low prevalence of HIV in this setting, the employee should be advised against taking HIV medications. Also, because she is HBsAb positive she is not a candidate for HBV PEP. The HCP should be advised to refrain from donating blood, plasma, organs, or tissue, to use barrier methods during sexual activities, and to refrain from sharing any injection or other drug use equipment. She should also be counseled about universal precautions and administration should take steps to reduce the risk of future accidental needle sticks. She should be educated about the symptoms of acute HIV and advised to return immediately if those symptoms occur. Mental health counseling should also be offered.

A baseline HIV antibody and anti-HCV should be drawn. HIV antibody should be repeated at 6 weeks, 3 months and 6 months after exposure. A 12-month followup is recommended if the source is found to be coinfected with HIV and HCV, or if the exposed becomes infected with HCV following exposure. Anti-HCV and ALT should be repeated within 4-6 months and if positive should be confirmed with supplemental tests.

2. A patient known to be HIV negative 6 months ago comes to the clinic stating that last night he was the receptive partner of unprotected sexual intercourse with his HIV-positive partner when the condom broke. His partner has been HIV-positive for 5 years, currently has an undetectable viral load, and is taking Combivir (zidovudine + lamivudine) and efavirenz (EFV). He has never had a resistance test.

Question: Should the patient take HIV PEP medications?

Answer:
Although the current recommendations for nonoccupational exposures were released in 1998 and at that time found that PEP for nonoccupational HIV exposure was still unproven, current data support treating. Receptive anal intercourse with an HIV-positive partner carries with it a risk of transmission of 0.5%-3.0%. Your patient's risk is likely lower because of his partner's low level of viremia. PEP in nonoccupational settings is modeled after PEP for HCPs. In this case, the patient had a large exposure from a known HIV-positive source with an undetectable viral load.

Following the model for PEP for HCPs, the patient should be treated ASAP, ie within 4 to 72 hours but not more than 72 hours after exposure and receive 2 medications, although some experts would recommend using 3 medications. It would be reasonable to place the patient on the same combination as his partner because his partner has exhibited good adherence and good virologic control. Treatment should continue for 28 days.

The patient should be counseled about medication side effects and the importance of adherence and followup. Common side effects should be anticipated and pre-empted with counseling and, in some cases, treatment. Changing medications and/or modifying the dosage regimen may increase the likelihood of completion of the HIV PEP regimen. And finally, the patient should be educated about the symptoms of acute HIV infection and advised to return immediately if those symptoms occur.

Question: What lab specimens should be drawn?

Answer:
A baseline HIV Ab should be drawn and repeated at 6 weeks, 3 months, 6 months and 12 months after exposure, as well as an HBsAg, HBsAb, and HCV Ab. If he were unvaccinated against HAV or HBV then vaccination should be initiated immediately. Laboratory monitoring for drug toxicity should be performed at baseline and then 2 weeks after initiating therapy. The medical record of the patient's partner should immediately be reviewed, and treatment for HBV, HCV, or other sexually transmitted diseases should occur, if any of these are found. Expert consultation should be sought if needed.