Notice to Readers Update: Provisional Public Health Service Recommendations For Chemoprophylaxis After Occupational Exposure to HIV
Although preventing blood exposures is the primary means of preventing occupationally acquired human immunodeficiency virus (HIV) infection, appropriate post-exposure management is an important element of workplace safety (1). Information suggesting that zidovudine (ZDV) postexposure prophylaxis (PEP) may reduce the risk for HIV transmission after occupational exposure to HIV-infected blood (2) prompted a Public Health Service (PHS) interagency working group *, with expert consultation **, to update a previous PHS statement on management of occupational exposure to HIV with the following findings and recommendations on PEP (1). *** Background
Although failures of ZDV PEP have occurred (3), ZDV PEP was associated with a decrease of approximately 79% in the risk for HIV seroconversion after percutaneous exposure to HIV-infected blood in a case-control study among health-care workers (2). In a prospective trial in which ZDV was administered to HIV-infected pregnant women and their infants, a direct effect of ZDV prophylaxis on the fetus and/or infant may have contributed to the observed 67% reduction in perinatal HIV transmission (4); the protective effect of ZDV was only partly explained by reduction of the HIV titer in maternal blood (5). PEP also prevented or ameliorated retroviral infection in some studies in animals (6,7).
The average risk for HIV infection from all types of reported percutaneous exposures to HIV-infected blood is 0.3% (3). In the case-control study (2), risk was increased for exposures involving
Although information about the potency and toxicity of antiretroviral drugs is available from studies of HIV-infected patients, it is uncertain to what extent this information can be applied to uninfected persons receiving PEP. In HIV-infected patients, combination therapy with the nucleosides ZDV and lamivudine (3TC) has greater antiretroviral activity than ZDV alone and is active against many ZDV-resistant HIV strains without significantly increased toxicity (8). Adding a protease inhibitor provides even greater increases in antiretroviral activity; among protease inhibitors, indinavir (IDV) is more potent than saquinavir at currently recommended doses and appears to have fewer drug interactions and short-term adverse effects than ritonavir (8). Few data exist to assess possible long-term (i.e., delayed) toxicity resulting from use of these drugs in persons not infected with HIV.
In currently recommended doses, ZDV PEP usually is tolerated well by health-care workers; short-term toxicity associated with higher doses primarily includes gastrointestinal symptoms, fatigue, and headache (3,7). The toxicity of other antiretroviral drugs in persons not infected with HIV has not been well characterized. In HIV-infected adults, 3TC can cause gastrointestinal symptoms and, in rare instances, pancreatitis. IDV toxicity includes gastrointestinal symptoms and, usually after prolonged use, mild hyperbilirubinemia (10%) and kidney stones (4%); the latter may be limited by drinking at least 48 oz (1.5 L) of fluid per 24-hour period (8). During the first 4 weeks of IDV therapy, the reported incidence of kidney stones was 0.8% (Merck Research Laboratories, unpublished data, 1996). As stated in the package insert, the concurrent use of IDV and certain other drugs, including some nonsedating antihistamines, is contraindicated. Based on limited data, ZDV use in the second and third trimesters of pregnancy and early infancy was not associated with serious adverse effects in mothers or infants (4,9); data are limited regarding the safety of ZDV during the first trimester of pregnancy or of other antiretroviral agents during pregnancy. Although 3TC has been associated with pancreatitis in HIV-infected children (8), whether 3TC causes fetal toxicity is unknown. Recommendations
The following recommendations are provisional because they are based on limited data regarding efficacy and toxicity of PEP and risk for HIV infection after different types of exposure. Because most occupational exposures to HIV do not result in infection transmission, potential toxicity must be carefully considered when prescribing PEP. When possible, these recommendations should be implemented in consultation with persons having expertise in antiretroviral therapy and HIV transmission. Changes in drug regimens may be appropriate, based on factors such as the probable antiretroviral drug resistance profile of HIV from the source patient; local availability of drugs; and medical conditions, concurrent drug therapy, and drug toxicity in the exposed worker. These recommendations were not developed to address nonoccupational (e.g., sexual) exposures.
Reported by: Center for Drug Evaluation and Research, Food and Drug Administration. AIDS Program Office, Health Resources and Svcs Administration. National Institute of Allergy and Infectious Diseases, Warren H. Magnuson Clinical Center, National Institutes of Health. National Center for HIV, STD, and TB Prevention (proposed); National Institute for Occupational Safety and Health; and National Center for Infectious Diseases, CDC.
* The interagency working group comprised representatives of CDC, the Food and Drug Administration (FDA), the Health Resources and Services Administration, and the National Institutes of Health. Information included in these recommendations may not represent FDA approval or approved labeling for the particular products or indications in question. Specifically, the terms "safe" and "effective" may not be synonymous with the FDA-defined legal standards for product approval.
** CDC and the National Foundation for Infectious Diseases cosponsored a workshop, HIV Post-Exposure Management for Health Care Workers, on March 4-5, 1996; proceedings of the workshop will be published in the American Journal of Medicine.
*** Single copies of this report will be available free until June 7, 1997, from the CDC National AIDS Clearinghouse, P.O. Box 6003, Rockville, MD 20849-6003; telephone (800) 458-5231 or (301) 217-0023.
**** An HIV strain is more likely to be resistant to a specific antiretroviral agent if it is derived from a patient who has been exposed to the agent for a prolonged period of time (e.g., 6-12 months or longer). In general, resistance develops more readily in persons with more advanced HIV infection (e.g., CD4+ T-lymphocyte count of less than 200 cells/mm3), reflecting the increasing rate of viral replication during later stages of the illness.
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TABLE 1. Provisional Public Health Service recommendations for chemoprophylaxis after occupational exposure to HIV, by type of exposure and source material -- 1996 ==================================================================================================== Type of Antiretroviral Antiretroviral exposure Source material * prophylaxis + regimen & Percutaneous Blood @ Highest risk Recommend ZDV plus 3TC plus IDV Increased risk Recommend ZDV plus 3TC, +/- IDV ** No increased risk Offer ZDV plus 3TC Fluid containing visible blood, other potentially infectious fluid ++, or tissue Offer ZDV plus 3TC Other body fluid (e.g., urine) Not offer Mucous membrane Blood Offer ZDV plus 3TC, +/- IDV ** Fluid containing visible blood, other potentially infectious fluid ++, or tissue Offer ZDV, +/- 3TC Other body fluid (e.g., urine) Not offer Skin, increased risk && Blood Offer ZDV plus 3TC, +/- IDV ** Fluid containing visible blood, other potentially infectious fluid ++, or tissue Offer ZDV, +/- 3TC Other body fluid (e.g., urine) Not offer ---------------------------------------------------------------------------------------------------- * Any exposure to concentrated HIV (e.g., in a research laboratory or production facility) is treated as percutaneous exposure to blood with highest risk. + Recommend -- Postexposure prophylaxis (PEP) should be recommended to the exposed worker with counseling (see text). Offer -- PEP should be offered to the exposed worker with counseling (see text). Not offer -- PEP should not be offered because these are not occupational exposures to HIV (1). & Regimens: zidovudine (ZDV), 200 mg three times a day; lamivudine (3TC), 150 mg two times a day; indinavir (IDV), 800 mg three times a day (if IDV is not available, saquinavir may be used, 600 mg three times a day). Prophylaxis is given for 4 weeks. For full prescribing information, see package inserts. @ Highest risk -- BOTH larger volume of blood (e.g., deep injury with large diameter hollow needle previously in source patient's vein or artery, especially involving an injection of source-patient's blood) AND blood containing a high titer of HIV (e.g., source with acute retroviral illness or end-stage AIDS; viral load measurement may be considered, but its use in relation to PEP has not been evaluated). Increased risk -- EITHER exposure to larger volume of blood OR blood with a high titer of HIV. No increased risk -- NEITHER exposure to larger volume of blood NOR blood with a high titer of HIV (e.g., solid suture needle injury from source patient with asymptomatic HIV infection). ** Possible toxicity of additional drug may not be warranted (see text). ++ Includes semen; vaginal secretions; cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluids. && For skin, risk is increased for exposures involving a high titer of HIV; prolonged contact, an extensive area, or an area in which skin integrity is visibly compromised. For skin exposures without increased risk, the risk of drug toxicity outweighs the benefit of PEP. ====================================================================================================
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