Non-occupational Postexposure HIV Prophylaxis

Doctors who manage patients with sexually transmitted infections may be confronted with the scenario of a patient requesting for non-occupational post-exposure (NO-PEP) HIV prophylaxis in the clinic. In such a situation, the physician should assess the likelihood that HIV will be transmitted as a consequence of the exposure, and advise the patient about the risks and benefits of treatment. Appropriate counseling must be given, and if the decision is made to treat, follow up care for potential side effects of medication, repeat HIV testing and reinforcement of counseling messages must be done.

Introduction
Antiretroviral therapy (ART) offered as PEP has become the standard of care for healthcare workers who have had occupational exposure to HIV. A case-control study has demonstrated that PEP with zidovudine was associated with an 81% decrease in the odds of HIV transmission with a percutaneous exposure in the occupational setting.1 Although there is no data to show that ART is effective at preventing transmission from non-occupational exposures, the principles of managing patients with recent HIV exposure are similar whether the exposure occurs in an occupational or non-occupational setting.

 
HIV Exposure Risk Assessment
A detailed and careful history of the exposure event is the first step in evaluating a patient.

Table 1 shows the risk of HIV transmission following a single percutaneous occupational, sexual, or injection drug exposure.2 Patients should be told that these are estimates, and in reality, the odds of infection with a specific exposure are hard to estimate because the risk of HIV transmission is affected by many factors such as the viral load of the infected person, presence of other sexually transmitted diseases, the size of the inoculum, and so forth. Certain sexual practices (receptive anal intercourse) carry much higher risk than others (insertive oral sex).

Generally, exposures to saliva, urine, tears and sweat are not though to be infectious, and the risk of HIV transmission from splashes of contaminated fluids to mucosal surface or non-intact skin has not been accurately quantified, although it is likely to be low.
 

Criteria for NOPEP against HIV
The following criteria should be used:

• There is high risk exposure (any unprotected anal or vaginal intercourse, receptive fellatio with ejaculation) with: (1) a partner known to be HIV-infected, or (2) in HIV-risk group (men who have sex with men, bisexual men, IV drug users, commercial sex workers), or (3) patient was raped.
• Patient must be counseled and make a commitment to safe sex
• Patient must make an informed decision regarding potential risks and benefits of the treatment offered
• Exposure must have taken place within the last 72 hours, as initiating PEP after 72 hours is not advised

Regimen
The Department of STI Control Clinic offers a triple drug combination of Combivir® (zidovudine 300mg/lamivudine 150mg) 1 tablet twice a day AND Kaletra® (lopinavir 200mg/rtionavir 50mg) 2 tablets twice a day both for a total of 28 days. The cost to the patient is approximately $1225.80

Side Effects
The drugs used can all cause GIT side effects i.e. nausea, diarrhoea, anorexia
ZDV: most side effects are dose-related; major side effect is haemtaological - anemia, granulocytopenia; pigmentation of nails reported
3TC: well-tolerated; rash, hair loss, vasculitis, photophobia, paraesthesia
Kaletra: diarrhea, nausea, headache, asthenia, rash, insomnia

Baseline Tests and Follow Up
Baseline HIV test is performed.

Full blood count, liver and renal function tests; these will detect any pre-existing abnormality prior to treatment and can be repeated if necessary.

Patients should be seen after 2 and 4 weeks to assess compliance and possible side effects of medication, as well as to reinforce prevention messages.

Counseling Patients
It is important to counsel patients that:

• There is no absolute proof that ART PEP decreases risk of HIV, although there is supportive evidence based on biologic plausibility, animal studies and in a single study on HCW
• The treatment is not 100% effective, as there have been documented cases of seroconversion after occupational exposures despite PEP
• Side effects will be encountered with medication
• Most importantly, issues of safer sex and how to prevent future exposures must be addressed

References

1. 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; 337:1485-90.
2. Katz MH, Gerbeding JL. Management of occupational and nonoccupational postexposure HIV prophylaxis. Current Inf Dis Reports 2002; 4:543-9.
3. Gerbeding JL. Prophylaxis for occupational exposure to HIV. Ann Intern Med 1996; 125:849-56.
4. Vittinghoff E, Douglas J, Judson F, et al. Per-contact risk of human immunodeficiency virus transmission between male sexual partners. Am J Epidemiol 1999; 150:306-11.
5. Peterman TA, Stoneburner RL, Allen JR, et al. Risk of human immunodeficiency virus transmission from heterosexual adults with transfusion-associated infections. JAMA 1988, 259:55-8. [Erratum, JAMA 1989; 262:502]
6. Kaplan EH, Heimer R. A model-based estimate of HIV infectivity via needle-sharing. J Acquir Immune Defic Send 1992; 5:1116-8.

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