Are HCWs spreading HCV in ambulatory care?

CDC investigates health care-related spread

Health care workers may be contributing to an undetected spread of hepatitis B and C in ambulatory care centers, a concern that has prompted an investigation by the Centers for Disease Control and Prevention (CDC).

Several large outbreaks have occurred in which health care workers improperly reused needles or contaminated multiuse vials and hundreds of patients contracted hepatitis B or C.

"The experience with these outbreaks is a little sobering. We have seen huge outbreaks," says Ian Williams, PhD, MS, chief of the Epidemiologic Research and Field Investigations Team in CDC’s Division of Viral Hepatitis. "These shouldn’t happen in the United States."

That led CDC investigators to ask: "Are there sporadic transmissions that we’re missing out there?"

A closer look at surveillance data further raises the concern. About 40% of those older than 70 who have acute hepatitis B or C have been hospitalized or had same-day surgery. Yet only 10% of people older than 65 say they have been hospitalized in the past six months, according to the National Health Interview Survey. Older adults presumably do not have the other major risk factors for hepatitis B or C — intravenous drug use and multiple sex partners.

"We don’t know exactly what this means, but it’s suggestive that something’s going on," says Williams.

The CDC is launching a study to compare the hospitalization and same-day surgery rates of people older than 60 who have acute hepatitis B or C and older people in the general population who do not.1 "If hospitalization really is more common among these cases than well-matched controls, then health care is a factor [in transmission]," he explains.

The study will not look at the possibility of health care worker-to-patient transmission or prevalence among health care workers.

As a group, health care workers have a prevalence of hepatitis C that is similar to or lower than the general population, Williams notes.

Infection control in ambulatory care

For now, the CDC is pondering a different question: What should be done to improve infection control practices? The concern is greatest in ambulatory care, where the recent outbreaks occurred.

For example, 69 HCV infections and 31 HBV infections were linked to an Oklahoma pain management clinic, where a nurse reused a syringe and needle for injections into a heparin lock of the patients’ IV line.

At a hematology/oncology clinic in Nebraska, 99 patients developed HCV infections linked to chemotherapy treatment.

"The investigation revealed that the health care worker responsible for medication infusions routinely used the same syringe to draw blood from patients’ central venous catheters and to draw catheter-flushing solution from 500 cc saline bags that were used for multiple patients," researchers concluded.2

"The guidelines are out there on injection safety and the possible contamination of multiuse vials," says Raymond Chinn, MD, hospital epidemiologist at Sharp Memorial Hospital in San Diego and leader of the ambulatory care working group of the Healthcare Infection Control Practices Advisory Committee (HICPAC), a CDC advisory panel. "The challenge is they’re not being followed."

HICPAC is partnering with other organizations to find ways to promote better infection control practices in ambulatory care centers, Chinn says.

"We think one of the key things that should happen is education and oversight," Williams explains. "You wouldn’t think you have to tell people not to reuse needles and syringes. But it’s happening, believe it or not."

References

1. Centers for Disease Control and Prevention. Proposed data collection submitted for public comment and recommendations. Fed Reg 2004; 69:43,594.

2. Transmission of hepatitis B and C viruses in outpatient settings — New York, Oklahoma, and Nebraska, 2000-2002. MMWR 2003; 52:901-906.