University of Zambia Medical Library

Occupational Exposure to HIV: Information for Health Care Workers
(Centers for Disease Control and Prevention -- U.S.)

IF AN EXPOSURE OCCURS:
Immediately following an exposure to blood:

• Needlesticks and cuts should be washed with soap and water.
• Splashes to the nose, mouth, or skin should be flushed with water.
• Eyes should be irrigated with clean water, saline, or sterile irrigants.

Following any blood exposure you should:

• Report the exposure to the department (e.g., occupational health, infection control) responsible for managing exposures.

RISK OF INFECTION AFTER EXPOSURE:,
While the risk is very low, it is not zero. HIV infection has been reported after occupational exposures to HIV-infected blood through needlesticks or cuts; splashes in the eyes, nose, or mouth; and skin contact. Exposures from needlesticks or cuts cause most infections. The average risk of HIV infection after a needlestick/cut exposure to HIV-infected blood is 0.3% (i.e., three-tenths of one percent, or about 1 in 300). Stated another way, 99.7% of needlestick/cut exposures do not lead to infection.

The risk after exposure of the eye, nose, or mouth to HIV-infected blood is estimated to be, on average, 0.1% (1 in 1,000). The risk after exposure of the skin to HIV-infected blood is estimated to be less than 0.1%. A small amount of blood on intact skin probably poses no risk at all. There have been no cases of HIV transmission documented due to an exposure involving a small amount of blood on intact skin. The risk may be higher if the skin is damaged (e.g., by a recent cut) or if the contact involves a large area of skin or is prolonged.

Risk from all exposures is probably increased if the exposure involves a larger volume of blood or a higher amount of HIV in the patient's blood. (Source-patients near death with AIDS or patients with symptoms of acute HIV infection usually have higher amounts of HIV in their blood.) As of December 1996, CDC had received reports of 52 documented cases and 111 possible cases of occupationally acquired HIV infection among Health Care Workers in the United States.

TREATMENT FOR THE EXPOSURE:
Results from a small number of studies suggest that the use of zidovudine (ZDV) and other antiviral drugs after certain occupational exposures may reduce the chance of HIV transmission. In one study the use of ZDV after HIV exposure from a needlestick or cut reduced the risk of HIV infection by almost 80%.

Studies suggest that postexposure treatment may prevent infection with HIV. However, because there have been at least 12 reported cases of ZDV failing to prevent HIV infection in health-care workers, postexposure treatment will probably not prevent all cases of infection transmission. P Post-exposure treatment is not recommended for all types of occupational exposures to HIV: Because most occupational exposures do not lead to HIV infection, the chance of possible serious side effects from the drugs used to prevent infection may be much greater than the chance of HIV infection from such exposures. Both risk of infection and possible side effects of drugs should be carefully considered when deciding whether to take postexposure treatment. Exposures with a lower infection risk may not be worth the risk of the side effects associated with these drugs.

If the source individual cannot be identified or tested, decisions regarding follow-up should be based on the exposure risk and whether the source is likely to be a person who is HIV positive. Follow-up HIV testing should be available to all workers who are concerned about possible HIV infection through occupational exposure.

TREATMENTS AVAILABLE:
In June 1996, the Public Health Service recommended that zidovudine (ZDV), lamivudine (3TC), and a protease inhibitor, preferably indinavir (IDV), be used as follows:

• ZDV should be considered for treatment of all exposures involving HIV-infected blood, fluid containing visible blood, or other potentially infectious fluid or tissue.
• 3TC should be added to ZDV for increased effectiveness and for use against ZDV-resistant types of virus. Used in combination, ZDV and 3TC are very effective in treating HIV infection, and considerable information shows that they are safe when used for a short time.
• IDV should be added for the highest risk exposures, such as those involving a larger volume of blood with a larger amount of HIV. IDV is a potent antiviral drug that appears to be safe when taken for a short period, although less information is available about the safety of this drug.

These recommendations are intended to provide guidance to clinicians and may be modified on a case-by-case basis. Whenever possible, consulting an expert with experience in the use of antiviral drugs is advised, especially if a recommended drug is not available, if the source patient's virus is likely to be resistant to one or more recommended drugs, or if the drugs are poorly tolerated. ZDV alone may be considered for some lower risk exposures when the virus is likely to be sensitive to the drug.

Treatment should be started promptly, preferably within 1-2 hours, after the exposure. Although animal studies suggest that treatment is not effective when started more than 24-36 hours after exposure, it is not known if this time frame is the same for humans. Starting treatment after a longer period (for example, 1-2 weeks) may be considered for the highest risk exposures; even if HIV infection is not prevented, early treatment of initial HIV infection may lessen the severity of symptoms and delay the onset of AIDS.

The optimal course of treatment is unknown; because 4 weeks of ZDV appears to provide protection against HIV infection, if tolerated, treatment should probably be taken for 4 weeks. The U.S. Food and Drug Administration has approved these drugs for the treatment of HIV infection, but not for preventing infection. However, physicians may prescribe any approved drug when, in their professional judgement, the use of the drug is warranted.

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Last updated November 20, 1997

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