More than 8 million health care workers in the United States work in hospitals and other health care settings. Precise national data are not available on the annual number of needlestick and other percutaneous injuries among health care workers; however, estimates indicate that 600,000 to 800,000 such injuries occur annually. About half of these injuries go unreported.
Data from the EPINet system suggest that at an average hospital, workers incur approximately 30 needlestick injuries per 100 beds per year. Most reported needlestick injuries involve nursing staff; but laboratory staff, physicians, housekeepers, and other health care workers are also injured. Some of these injuries expose workers to bloodborne pathogens that can cause infection.
The most important of these pathogens are HBV, HCV, and HIV. Infections with each of these pathogens are potentially life threatening and preventable.
Between 1985 and June 1999, cumulative totals of 55 documented cases and 136 possible cases of occupational HIV transmission to U.S. health care workers were reported to the Centers for Disease Control and Prevention (CDC). Most involved nurses and laboratory technicians. Percutaneous injury (e.g., needlestick) was associated with 49 (89%) of the documented transmissions. Of these, 44 involved hollow-bore needles, most of which were used for blood collection or insertion of an IV catheter.
HIV infection is a complex disease that can be associated with many symptoms. The virus attacks part of the body’s immune system, eventually leading to severe infections and other complications, a condition known as AIDS.
Health care workers who were investigated and (1) had no identifiable behavioral or transfusion risks, (2) reported having had percutaneous or mucocutaneous occupational exposures to blood or body fluids or to laboratory solutions containing HIV, but (3) had no documented HIV seroconversion resulting from a specific occupational exposure.
Information from national hepatitis surveillance is used to estimate the number of HBV infections in health care workers. In 1995, an estimated 800 health care workers became infected with HBV [CDC unpublished data]. This figure represented a 95% decline from the 17,000 new infections estimated in 1983. The decline was largely due to the widespread immunization of health care workers with the hepatitisB vaccine and the use of universal precautions and other measures required by the Occupational Safety and Health Administration (OSHA) bloodborne pathogens standard. About one-third to one-half of persons with acute HBV infection develop symptoms of hepatitis such as jaundice, fever, nausea, and abdominal pain. Most acute infections resolve, but 5% to 10% of patients develop chronic infection with HBV that carries an estimated 20% lifetime risk of dying from cirrhosis and 6% risk of dying from liver cancer.
Hepatitis C virus infection is the most common chronic bloodborne infection in the United States, affecting approximately 4 million people. Although the prevalence of HCV infection among health care workers is similar to that in the general population (1% to 2%), health care workers clearly have an increased occupational risk for HCV infection.
In a study that evaluated risk factors for infection, a history of unintentional needlestick injury was independently associated with HCV infection. The number of health care workers who have acquired HCV occupationally is not known. However, of the total acute HCV infections that have occurred annually (ranging from 100,000 in 1991 to 36,000 in 1996), 2% to 4% have been in health care workers exposed to blood in the workplace.
HCV infection often occurs with no symptoms or only mild symptoms. But unlike HBV, chronic infection develops in 75% to 85% of patients, with active liver disease developing in 70%. Of the patients with active liver disease, 10% to 20% develop cirrhosis, and 1% to 5% develop liver cancer.
RISK OF INFECTION AFTER A NEEDLESTICK INJURY
After a needlestick exposure to an infected patient, a health care worker’s risk of infection depends on the pathogen involved, the immune status of the worker, the severity of the needlestick injury, and the availability and use of appropriate post exposure prophylaxis.