Occupational exposures to HIV
Occupational exposure to HIV can result from a needlestick injury, cut with a sharp object, or contact with potentially infectious body fluids to mucous membranes or skin that is not intact (chapped, cut, abraded, inflamed). Body fluids that are considered potentially infectious are listed in TABLE 2, along with fluids not considered to be infectious.
The risk of contracting HIV from an occupational exposure is determined by several factors, but is generally low. The risk of infection after a needle-stick injury with exposure to infected blood is estimated at 0.3%; after a mucous membrane exposure, 0.09%. The risk after exposure to nonintact skin is probably even lower. Risk increases with the quantity of blood exposed to, a needle-stick injury directly into a vein or artery, and deep injuries.
TABLE 2
Which body fluids are infectious?
| BODY FLUIDS POTENTIALLY INFECTIOUS FOR HIV | |
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| BODY FLUIDS NOT CONSIDERED TO BE INFECTIOUS UNLESS THEY ARE VISIBLY BLOODY | |
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Who should and should not receive PEP
TABLE 1 details recommended treatment responses to specific types of exposure (eg, puncture wound) and the status of the exposure source.4 In situations unlikely to result in disease transmission (superficial injury and source patient with unknown HIV status), no PEP is generally warranted due to the low risk of infection and potential toxicity of antiretrovirals.
Treatment particulars
Start postexposure prophylaxis, when indicated, as soon as possible following exposure and continue it for 4 weeks. Obtain baseline test results for HIV at the time of exposure and periodically for 6 months. The CDC recommends testing at 6 weeks, 12 weeks, and 6 months, whether or not PEP is provided.
Testing and monitoring for hepatitis B and C may also be indicated.
Advise patients on PEP to use precautions in avoiding the possibility of secondary transmission, especially in the first 3 months following exposure. Monitor for drug toxicity every week or 2 while giving PEP. Because of the complexity of potential PEP regimens and the risk for drug toxicity, you may want to take advantage of several national sources of consultation, such as the PEPline (www.ucsf.edu/hivcntr/Hotlines/PEPline or 888-448-4911) or the HIV/AIDS Treatment Information Service (aidsinfo.nih.gov)—especially with questions about potential drug resistance or if the exposed person is pregnant.
When risk is real but low, 2-drug PEP is recommended (TABLE 1), usually 2 nucleoside reverse transcriptase inhibitors (NRTI) or 1 NRTI and 1 nucleotide reverse transcriptase inhibitor (NtRTI).
For those at higher risk, 3 or more antiviral regimens are recommended, achieved by adding a protease inhibitor to one of the recommended 2-drug regimens. The potential antiviral combinations in the basic 2-drug and expanded PEP regimens, along with potential side effects and toxicities of antiviral medications are described in TABLE W1, available online at www.jfponline.com.4
Nonoccupational exposures rarely require PEP
There are many unresolved questions regarding PEP for nonoccupational exposures. The lack of definitive evidence of its effectiveness, its unknown influence on risk-taking behavior, and the potential to aggravate viral resistance have led CDC to recommend that PEP be used only infrequently and not continuously for those whose behavior results in frequent exposures.3 Those who continue to participate in high risk activities should be referred for risk-reduction behavioral counseling.
The risk of HIV transmission varies by route and source of exposure (TABLE 3). The CDC has developed an algorithm based on these variables (FIGURE) to help you decide whether to initiate PEP. Two situations that cause concerns but pose little known risk of infection are bites and needlestick injuries from discarded needles; PEP is rarely indicated for either.
As with occupational exposure PEP, those receiving nonoccupational PEP should be evaluated at baseline for HIV infection. In addition, consider evaluating them for other STD’s and pregnancy.
As with occupational exposure, start nonoccupational PEP as soon as possible and continue it for 28 days. Nonoccupational PEP is not recommended if time after exposure is more than 72 hours. A 3-drug regimen is recommended by the CDC for nonoccupational exposures, even though evidence is lacking that it provides superior benefit over 2 drugs (see TABLE W1 at www.jfponline.com).
Follow-up recommendations for those provided nonoccupational PEP are the same as for occupational PEP, and testing for other STDs and hepatitis B and C is also recommended (TABLE 4).
FIGURE
Evaluation and treatment of possible nonoccupational HIV exposures
Source: Centers for Disease Control and Prevention 2005.3
TABLE 3
Estimated per-act risk for acquisition of HIV, by exposure route*