Lowering the Risk

Despite safeguards, occupational blood exposure continues to occur and needs to be viewed as an urgent health issue.

• By Judith Green-McKenzie, M.D., MPH, FACOEM, FACP, Marilyn Watkins, MSN, CRN
• Apr 01, 2005

EXPOSURE to bloodborne pathogens (BBPs) is an occupational hazard for many workers, including, among others, health care workers, law enforcement officers, fire service personnel, funeral service employees, body piercers, day care workers, environmental service workers, and wastewater workers. BBPs are microorganisms present in human blood that can potentially cause disease in humans.¹ The BBPs of main concern are human immunodeficiency virus (HIV), Hepatitis B virus (HBV), and Hepatitis C virus (HCV).

Exposure to blood presents the highest risk for the transmission of BBPs in the occupational setting.² HIV causes the acquired immunodeficiency syndrome. Both HBV and HCV can cause chronic hepatitis, cirrhosis, liver cancer, and liver failure.

Occupational Exposure
An occupational exposure occurs when a worker experiences a percutaneous injury, mucous membrane contact, or skin contact with potentially infected blood or body fluid. The percutaneous injury may be from a needle or other sharp object. Mucous membrane contact may occur after a splash to the eyes, nose, mouth, or throat. Skin that is abraded or otherwise compromised due to a cut, rash, or break can assist transmission by providing a portal of entry.

Not all body fluids are considered potentially infectious. Body fluids containing visible blood, semen, and vaginal secretions are considered potentially infectious fluids, as are fluids from around the lungs, heart, and abdominal wall. Concentrated virus in a research lab is also considered potentially infectious. However, sweat, tears, nasal secretions, saliva, sputum, vomit, urine, and feces are not considered infectious unless blood is present in these fluids.³

It is estimated that the risk of developing HIV infection after experiencing a percutaneous injury with an HIV contaminated needle is 0.3 percent. The risk of being infected with HBV after a percutaneous injury if the needle has blood contaminated with HBV is 27 percent to 37 percent, and the risk is 1.8 percent if the needle has blood contaminated with HCV.

If the exposure to contaminated blood is via the mucous membranes, the risk of developing HIV infection is 0.09 percent. The risk from exposure of non-intact skin to contaminated blood is unclear but less than the risk from mucous membrane exposure. The risk from a bite has not been quantified; however, both the victim and the biter need to be evaluated by a health care provider who can then assess the risk and decide on treatment.^3,4

Formal Efforts to Reduce Exposure
Various strategies designed to reduce the risk of occupational exposure to BBPs have been recommended and implemented during the past three decades. Much of what has been written has concerned health care personnel. However, the same exposure and management principles can be applied to other workers.³

Formal efforts to help prevent transmission of the HIV virus in the health care setting started in the early 1980s when the Centers for Disease Control and Prevention recommended the use of Universal Precautions (UP). The underlying premise of UP is that all blood and body fluids should be treated as if they are potentially infectious for HIV, HBV, HCV, and other BBPs. Work practices consistent with UP include the use of personal protective barrier equipment, such as gloves, masks, gowns, and protective eyewear, when there is a potential for exposure to blood and body fluids. Masks and protective eyewear should reduce the incidence of contamination of mucous membranes of the nose, mouth, and eyes. Other elements of UP are that sharp objects should be disposed of in puncture-resistant containers, needles and other sharp instruments should be used with caution, and needles should not be recapped.⁵

These CDC recommendations were updated in 1987, and in 1991 the Occupational Safety and Health Administration promulgated the Bloodborne Pathogens Standard with the intent to help prevent BBP exposures in the workplace. This standard, which covers all workers with recognized risk of exposure to BBPs, went into effect a few months later, requiring employers to establish an exposure plan designed to eliminate or minimize employee exposure to BBPs; to be responsible for educating and training exposed workers on BBPs; to provide accessible engineering controls such as sharps disposal containers to employees; and to provide accessible personal protective equipment, such as gloves, gowns, and pocket masks in order to eliminate or minimize employee exposure. Under the standard, employers also are required to maintain a clean workplace and adequately communicate hazards, such as potentially infectious waste, to employees. UP is an important part of the standard.^1,6

In an effort to further decrease needlesticks and other sharps injuries, OSHA revised the BBP standard in 2001 with the intent to help ensure implementation of new developments in safe needle technology. The revised standard requires employers to select safer needle devices as they become available and to involve employees in identifying and choosing the devices.³ The introduction of sharps, such as needles and intravenous catheters, that possess safety engineered features (engineered sharps injury prevention devices) has been shown to lead to a decrease in percutaneous injuries.^7,8

Medical Intervention After an Exposure
The standard requires that employers provide confidential medical post-exposure evaluation and follow-up for workers with occupational exposure to BBPs who are covered by the standard. Under the standard, employers must provide the HBV vaccine to all employees at risk for exposure to HBV.¹ But even when the HBV vaccine is made available, not all eligible workers choose to be vaccinated.⁹ As such, many workers remain unprotected from HBV.

Post-exposure prophylaxis (PEP) is available to HBV-exposed workers who are not immune to HBV, in the form of HBV vaccine and hepatitis B immune globulin (HBIG). HBIG is 75 percent effective in protecting against HBV infection, and serious adverse side effects are rare when it is administered appropriately. It is best to give PEP for HBV as soon as possible after exposure because the effectiveness of HBIG seven days post-exposure is not known.³

There is no cure or effective vaccine for Acquired Immune Deficiency Syndrome, but PEP in the form of HIV antiretroviral drugs given soon after occupational exposure decreases the risk of infection. In the event of an exposure, medical treatment and follow-up should be sought immediately so that PEP can be administered timely. PEP for HIV given 24 to 36 hours after infection is less effective than if it is given sooner. There is no vaccine or PEP available for HCV, although treatment with interferon soon after HCV transmission to an exposed worker is associated with a higher rate of resolved infection than if no treatment was given.^1,3,4

An Urgent Health Issue
In summary, workers from several occupations are at risk of exposure to BBPs during the course of their work. Prevention of occupational blood exposure is the primary way to prevent transmission of BBPs, and efforts made in recent decades to prevent and reduce such potential exposure have met with some success.³ This includes universal precautions; promulgation of the BBP standard, which requires engineering and work practice controls; PPE and the provision of post-exposure evaluation and follow-up; and, most recently, revision of the BBP standard requiring the use of engineered sharps injury prevention devices.,P> Despite these safeguards, BBP exposures continue to occur and need to be viewed as an urgent health issue. Hospital protocols need to promote expeditious treatment of these exposures.

Health care workers familiar with post-exposure treatment and follow-up after a BBP exposure should be available to workers with the potential for occupational BBP exposures. Local experts and national resources such as the national clinicians hotline (888-448-4911) can be consulted.⁴ Knowledge of how to access appropriate medical care in a timely manner in the event of an exposure can decrease the chances of an individual acquiring a life-threatening infection while at work.

References
1. United States Department of Labor, Occupational Safety and Health Administration. Occupational Exposure to Blood-borne pathogens--Final Rule. 29CFR Section 1910.1030. Fed Register. Dec. 6, 1991.
2. Centers for Disease Control and Prevention. "Guidelines for prevention of transmission of human immunodeficiency virus and hepatitis virus to healthcare and public safety workers. A response to P.L. 100-607. The Health Omnibus Programs Extension Act of 1988." MMWR. 1989; 38(5-7): 3-37.
3. "Updated U.S. 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): 1-52.
4. Gerberding JL. "Occupational Exposure to HIV in Health Care Settings." N Engl J Med. 2003; 348: 826-844.
5. Centers for Disease Control. "Recommendations for preventing transmission of infection with human T-lymphotropic virus type III/lymphadenopathy-associated virus in the workplace." MMWR 1985; 34: 681-686, 691-695.
6. Centers for Disease Control. "Recommendations for prevention of HIV transmission in health-care settings." MMWR 1987; 36: 1S-18S.
7. Perry J, Parker G, Jagger J. "EPINet Report: 2001 Percutaneous Injury Rates." Advances in Exposure Prevention. 2003; 6: 32-37.
8. Mendelson MH, Bao YL, Solomon R, et. al. "Evaluation of a Safety Resheathable Wing Steel Needle for prevention of percutaneous injuries associated with Intravascular-Access procedures among Health Care Workers." Infect Control Hosp Epidemiol. 2003; 24: 105-112.
9. Behrman AJ, Shofer F, Green-McKenzie J. "Trends in bloodborne pathogen exposure and follow-up at an urban teaching hospital:1987 to 1997." J Occup Environ Med. 2001; 43: 370-376.

This article appeared in the April 2005 issue of Occupational Health & Safety.

This article originally appeared in the April 2005 issue of Occupational Health & Safety.