Is HCV emerging as greater threat on the job than HIV?

The emerging portrait of hepatitis C virus (HCV) as a risk to health care workers is not pretty. On the contrary, HCV poses a low, but real, risk to health care workers of acquiring a chronic, life-threatening occupational infection for which there is no vaccine, no post-exposure prophylaxis, and severely limited treatment options.

With a greater likelihood of infection per blood exposure, it can be argued that HCV now poses an overall risk to health care workers that exceeds HIV, says Donald Fry, MD, chairman of the department of surgery at the University of New Mexico Hospital in Albuquerque. Citing seroconversion rates as high as 10% following needlesticks with HCV-infected blood (as opposed to the 0.3% risk of infection in a comparable situation with HIV), Fry drew the comparison at a recent medical symposium in Los Angeles.

"HIV gets the headlines, but I would argue for you today as practitioners that HCV is a bigger occupational risk," Fry said, personalizing the threat by recalling a recent operation he performed on a gunshot victim who bled profusely during surgery.

"He is going to survive, but I'm not sure I, my residents, or my medical student will -- since we have subsequently found out that he is indeed a chronic hep C-positive patient," he said. "It is a risk to all of you -- it is a risk to me."

Fry's concern is borne out by several studies recently cited by the Centers for Disease Control and Prevention in an unpublished draft report on HCV. In studies that reported on the follow-up of health care workers who sustained percutaneous exposures to blood from anti-HCV positive patients, the incidence of subsequent HCV seroconversion averaged 3.5%.1-4 In addition, a study that used polymerase chain reaction (PCR) to measure HCV infection by detecting HCV RNA found the incidence was 10%.5

The CDC also cited seroprevalence studies reporting the presence of HCV antibodies in 1% of hospital workers in Western countries, and found a history of needlesticks was associated with anti-HCV positivity.6,7 In addition to HCV transmission to health care workers via needlesticks or cuts with sharp instruments, there is one report of transmission following a blood splash to the eyes.8

"Although it seems clear that needlestick exposure to infectious blood is a risk factor for hepatitis C, the data are limited or nonexistent on the risk of transmission associated with other types of occupational exposures, making it difficult to provide health care workers who sustain such exposures with a meaningful estimate of their chances of developing HCV infection," the CDC draft stated.

Of particular concern for those who develop infection is that virtually all people with acute HCV infection become chronically infected, and chronic liver disease with persistently elevated liver enzymes develops in an average of 67%, the CDC reported.

Unfortunately, post-exposure prophylaxis with immune globulin appears ineffective in preventing HCV. A recent experimental study in chimpanzees found that immune globulin administered one hour after exposure to HCV did not prevent infection or disease.9 In February 1994, the CDC's immunization practices advisory committee reviewed the available data and concluded there was no support for the use of immune globulin for post-exposure prophylaxis of HCV.

References

1. Hernandez ME, Bruguera M, Puyuelo T, et al. Risk of needlestick injuries in the transmission of hepatitis C virus in hospital personnel. Hepatology 1992; 16:56-58.

2. Zuckerman J, Clewley G, Griffiths P, et al. Prevalence of hepatitis C antibodies in health care workers. Lancet 1994; 343:1,618-1,620.

3. Petrosilla N, Puro V, Ippollito G, et al. Prevalence of hepatitis C antibodies in health care workers. Lancet 1994; 344:339-340.

4. Lanphear BP, Linneman CC, Cannon CG, et al. Hepatitis C virus infection in health care workers: risk of exposure and infection. Infect Control Hosp Epidemiol 1994; 15:745-750.

5. Mitsui T, Iwano K, Masuko K, et al. Hepatitis C virus infection in medical personnel after needlestick accident. Hepatology 1992; 16:1,109-1,114.

6. Alter MJ. Epidemiology of hepatitis C in the West. Semin Liver Dis 1995; 15:5-14.

7. Polish LB, Tong MJ, Co RL, et al. Risk factors for hepatitis C virus infection among health care personnel in a community hospital. Am J Infect Control 1993; 21:196-200.

8. Sartori M, La Terra G, Aglietta M, et al. Transmission of hepatitis C via blood splash into conjunctiva. Scand J Infect Dis 1993; 25:270-271.

9. Krawczynski K, Alter MJ, Tankersley DL, et al. Studies on protective efficacy of hepatitis C immunoglobulin (HCIG) in experimental hepatitis C virus infection [abstract]. Hepatology 1993; 18:110A. *