Human immunodeficiency virus, or HIV, is spread through contact with infected blood and body fluids. The risk of transmission varies according to the manner of exposure. The risk is greatest with transfusion of contaminated blood, needle sharing, unprotected intercourse with an infected individual and needle sticks in a health care setting when the needle has been used for an HIV-positive patient. Fortunately several medication regimens are available to prevent the spread of the virus after exposure.
Occupational Exposure
Health care workers may be exposed to HIV through a needle injury or from splashing blood or body fluid. The degree of exposure determines the recommended treatment regimen. A less-severe exposure, such as a superficial needle stick or splash of a small amount of blood from an HIV-positive patient, is usually treated with a two-drug regimen. For those subjected to a more significant risk, such as a deep puncture or large-volume blood splash, a threedrug combination may be recommended. Treatment should be initiated within 72 hours if possible, and is continued for 28 days. Post -exposure treatment is generally not required if the source of the exposure is HIV-negative or if the HIV status is unknown, unless there is a high likelihood of HIV introduction.
The preferred two drug treatment plans use the medicine zidovudine plus lamivudine or emtricitabine. Other options are lamivudine plus tenofovir or enofovir plus emtricitabine. When a third medicine is recommended, lopinavir/ritonavir is used with one of the above double drug combinations.
Nonoccupational Exposure
Victims of sexual assault, or those who are exposed to HIV through a mucus membrane or through skin damage, should use a three-drug strategy of treatment. If it has been more than 72 hours since the incident, or if the risk of HIV transmission is considered low, no treatment is generally recommended.
The three-drug treatment regimens usually consist of efavirenz plus lamivudine or emtricitabine plus zidovudine or tenofovir. Another three-drug option includes lopinavir/ritonavir plus lamivudine or emtricitabine plus zidovudine
Special Circumstances
Many cases of HIV exposure are not straightforward and must be handled on a case-by-case basis with professional consultation. However, some guidelines are available. Pregnant women with HIV are generally prescribed an appropriate therapeutic regimen in an attempt to prevent transmission to the fetus, but not all available drugs are safe in pregnancy. If a woman is exposed to HIV while pregnant, efavirenz should be avoided, but she may be offered other options. Children who come in contact with the virus may also be administered preventative medicine tailored specifically for their age.
References
- CDC: Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the U.S.
- CDC: Updated U.S. Public Health Service Guidelines for the Management of Occupational Expsures to HIV and Recommendations for Postexposure Prophylaxis
- American Family Physician: Postexposure Prophylaxis Against Human Immunodeficiency Virus
