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Occupational exposure to blood-borne pathogens?especially HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV)?in the health care setting is a serious problem.1,2
Needle-stick injuries occur through needle sticks and cuts from sharp instruments contaminated with an infected patient?s blood. The exact annual number of these injuries among health care workers in the United States is unavailable. The National Institute for Occupational Safety and Health, however, estimates that 600,000 to 800,000 sharps injuries occur annually.3 In 2003, data from the Exposure Prevention Information network system showed that, at an average hospital, health care personnel incur ~24 percutaneous injuries per 100 beds per year.4,5
The emotional impact and anxiety from a needle-stick injury involving contaminated blood can be severe and long-lasting, even when a serious infection is not transmitted. Although postexposure prophylaxis (PEP) reduces the transmission risk, it does not eliminate it, so avoiding needle-stick injuries is crucial.6,7
Various regulatory agencies have developed guidelines and legislation to help prevent needle-stick injuries. In 1991, the Occupational Safety and Health Administration issued the Bloodborne Pathogens Standard (BPS). In 2000, Congress passed the Needle-stick Safety and Prevention Act, and, in response, the amended 2001 BPS requires safer needle devices and has employers maintaining a log of injuries from contaminated sharps.8,9
Treatment and Postexposure Prophylaxis
In general, a health care worker?s risk after a needle-stick injury depends on the pathogen involved, the worker?s immune status, the severity of the injury, and the availability and use of appropriate PEP.
Needle-stick injuries involving solid needles, superficial injuries, or small amounts of blood carry smaller risks of viral transmission than those involving large-bore hollow needles, deep punctures, visible blood on the device, needles used in a patient?s artery or vein, or large amounts of blood.1,2,9
The Centers for Disease Control and Prevention?s (CDC) guidelines for the management of occupational exposures to HBV, HCV, and HIV recommend washing immediately with soap and water all wounds and skin sites that have been in contact with blood and body fluids. The guidelines recommend flushing with water exposed mucous membranes.
Using antiseptics or squeezing the wound does not decrease the blood-borne pathogen transmission risk. In addition, caustic agents, such as bleach, and the injection of antiseptics or disinfectants into the wound are not recommended. Employers should follow all federal and state requirements for reporting occupational injuries.1,2
The average risk for HIV transmission after a percutaneous exposure to HIV-infected blood is ~0.3% and after mucous membrane contact, 0.09%. The CDC guidelines for HIV PEP are based on the exposure source, type, and severity.2,10
Data in humans on the efficacy of HIV PEP are conflicting. Because seroconversion occurs infrequently, several thousand study participants would be needed to demonstrate efficacy. One small retrospective case-control study showed a risk reduction of 81% in health care workers who were given zidovudine as PEP.11 Another zidovudine study in HIV-infected pregnant women and their infants, however, demonstrated a risk reduction of 67%.12 Nevertheless, the CDC recommends initiating PEP as soon as possible (within hours as opposed to days) after exposure.1
Five antiretroviral classes are available in the United States: nucleoside reverse transcriptase inhibitors, nucleotide reverse transcriptase inhibitors, non?nucleoside reverse transcriptase inhibitors, protease inhibitors, and a single fusion inhibitor. Choosing a PEP regimen is primarily empiric, and selection must balance the risk of infection with the potential toxicity (ie, toxicity frequency, severity, duration, and reversibility). Table 1 shows the CDC?s 2005 recommendations for Basic and Expanded HIV PEP Regimens.
Although the optimal duration of PEP is unclear, if possible all patients should complete a 4-week course of therapy. Because of antiretroviral-associated toxicity, many patients are unable to tolerate an entire 4-week course. If clinicians are unsure as to which antiretroviral drug regimen should be used, they should start the basic regimen rather than delay PEP therapy. A consultation hot line, PEPline (888-448-4911), is available 24 hours a day to help clinicians identify appropriate PEP.2
HBV transmission risk is related to the degree of contact with blood and the source person?s hepatitis B e antigen status (HBeAg). Hepatitis B surface antigen (HBsAg)?positive patients who are HBeAg-positive have greater viral loads and thus are more likely to transmit the virus than those who are HBeAg-negative. After a needle-stick injury from a needle contaminated with HBsAg-positive and HBeAg-negative blood, the risk of developing serologic evidence of hepatitis B is ~23% to 37%, with a 1% to 6% risk of developing clinical hepatitis. If the source blood is HBsAg-positive and HBeAg-positive, there is a 37% to 62% risk for developing serologic evidence of hepatitis, with the risk for clinical hepatitis ~22% to 31%.1
Ideally, all health care workers should receive the hepatitis B vaccine during orientation or training. Health care workers immune to HBV (ie, those who developed antibodies from pre-exposure vaccination or prior infection) are not at risk for HBV.
Although not studied in the occupational PEP setting, HBV PEP regimens generally employ hepatitis B immune globulin (HBIG) alone or with the hepatitis B vaccine series. If initiated within 1 week following percutaneous exposure to HBsAg-positive blood, PEP provides an estimated 75% protection from HBV infection. The most common toxicities from the vaccination series include injection-site pain and mild-to-moderate fevers. Local pain and injection-site tenderness, urticaria, angioedema, and anaphylactic reactions also have been associated with HBIG.1
HCV, the most common chronic blood-borne infection in the United States, infects ~4 million people. Although the prevalence of HCV infection among health care workers reflects that of the general population (1% to 2%), health care workers are at an increased occupational risk. The serologic conversion rate for HCV after a needle-stick injury is ~1.8%.1
The CDC provides no recommendations for the use of antiviral agents, such as interferon with or without ribavirin, and there are no clinical studies to support their use as HCV PEP. The CDC recommends close follow-up and management for early identification of chronic disease and subsequent treatment referral options.1
Although HBV exposure poses a high infection risk, PEP can significantly reduce this risk. PEP reduces HCV and HIV infection risk to a lesser extent, however. Thus, preventing needle-stick injury is the best approach and an important part of any blood-borne pathogen prevention program.
1. Centers for Disease Control and Prevention. Updated US Public Health Service guidelines for the management of occupational exposures to HBV, HCV, and HIV and recommendations for postexposure prophylaxis. MMWR. 2001;50(RR-11):1-42.
2. Centers for Disease Control and Prevention. Updated US Public Health Service guidelines for the management of occupational exposures to HIV and recommendations for postexposure prophylaxis. MMWR. 2005; 54(RR-9):1-17.
3. NIOSH Alert: Preventing Needlestick Injuries in Health Care Settings. Available at: www.cdc.gov/niosh/2000-108.html#3. Accessed June 21, 2007.
4. International Health Care Worker Safety Center. Annual number of occupational percutaneous injuries and mucocutaneous exposures to blood or potentially infective biological substances. Available at: www.healthsystem.virginia.edu/internet/epinet/estimates.cfm. Accessed June 21, 2007.
5. Perry J, Parker G, Jagger J. EPINet report: 2003 percutaneous injury rates. Advances in Exposure Prevention. 2005;7(4):42-45.
6. Zanni GR, Wick JY. Preventing needlestick injuries. Consult Pharm. 2007;22(5):400-409.
7. Calfee DP. Prevention and management of occupational exposures to human immunodeficiency virus (HIV). Mt Sinai J Med. 2006;73(6):852-856.
8. Occupational Safety and Health Administration. Bloodborne pathogens standard. 29 CFR 1910 1030 2001.
9. Needlestick Safety and Prevention Act. 106th Congress of the United States of America. Public Law 106-430; H.R. 5178.
10. Campos-Outcalt D. HIV postexposure prophylaxis: Who should get it? J Fam Pract. 2006;55 (7):600-604.
11. LaFon SW, Mooney BD, McMullen JP, et al. A double-blind, placebo-controlled study of the safety and efficacy of Retrovir (zidovudine, ZDV) as a chemoprophylactic agent in health care workers exposed to HIV [abstract 489]. In: Program and Abstracts of the 30th Interscience Conference on Antimicrobial Agents and Chemotherapy. Atlanta, GA: American Society for Microbiology; 1990:167.
12. Connor EM, Sperling RS, Gelber R, et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. N Engl J Med. 1994;331:1173-1180.