Healthcare Infection Prevention-Smoke, but no HCV fire in first responders

CDC cites testing woes in Philadelphia study

Setting the record straight after some false-positive test data for hepatitis C virus heightened concerns about firefighters, the Centers for Disease Control and Prevention emphasizes that first responders are not at greater risk of acquiring HCV occupationally.

"We certainly acknowledge that they have exposures to blood and therefore are at risk, but we did not find that they were at increased risk," says Deblina Datta, MD, an officer in the CDC's Epidemic Intelligence Service. After some testing results of Philadelphia firefighters suggested heightened risk, the CDC received inquiries about the prevalence of hepatitis infection among first responders and the need for routine HCV testing.

"There were newspaper reports about the prevalence of HCV among firefighters, and CDC received inquiries from different health departments throughout the country," she says. "They were being asked to look into the issue by their own firefighters. So we undertook the study after receiving all of these reports and questions."

Reviewing five studies of HCV infection among first responders, the CDC found firefighters and paramedics are at no greater risk than the general population for HCV infection.¹ (See table, p. 4.) The situation began last year, when a testing company offered HCV testing kits to 4,400 active and retired members of the Philadelphia firefighters union. In February 2000, it was reported that 4.5% of the firefighters screened HCV positive, more than twice the national average of 1.8%. The calls and questions came in to the CDC, including one from Katherine West, BSN, MSEd, CIC, an infection control consultant in Manassas, VA, who has been specializing in fire and safety issues for years. "I questioned it," she says. "It just didn't make any sense to me for firefighters. EMS is done by a separate entity in Philadelphia, so that just didn't make any sense to me. The standard of care is that there must be confirmation testing with RIBA [recombinant immunoblot assay]. The first thing I questioned was, had confirmatory testing been done?"

Indeed, the CDC found discrepancies in confirmatory testing and discovered that 20.6% of the serum samples classified as positive were of insufficient volume to complete testing as required by the Food and Drug Administration. Reanalysis of the data indicated that the HCV rate was 3% in the Philadelphia group, and those positive primarily had nonoccupational risk factors.

CDC estimates indicate that three risk factors account for most HCV infections: illicit drug use (60%), high-risk sexual behavior (15%), and blood transfusion (7%). Health care workers and first responders exposed to blood in the workplace are at risk for infection by bloodborne pathogens. However, their risk for acquiring HCV infection is low because HCV is not transmitted efficiently through occupational exposure.

After an unintentional needlestick from an HCV-positive source, the average risk for HCV infection is 1.8% (range: 0%-7%); transmission rarely occurs from mucous membrane exposures to blood, and no transmission has been documented from intact or nonintact skin exposures to blood. First responders should continue to follow standard precautions and report sharps injuries and blood exposures, the CDC recommends. Routine HCV testing is not recommended.

Reference

1. Centers for Disease Control and Prevention. Hepatitis C virus infection among firefighters, emergency medical technicians, and paramedics — selected locations, United States, 1991-2000. MMWR 2000; 49:660-665.