CDC recommends HCV exposure follow-up
Source testing, HCW education advised
Health care institutions should consider implementing policies and procedures for hepatitis C follow-up for health care workers after percutaneous or permucosal exposure to blood, according to recommendations issued recently by the U.S. Centers for Disease Control and Prevention.1
The recommendations, published in the Morbidity and Mortality Weekly Report, are substantially similar to the agency’s 1995 guidelines included in a hepatitis surveillance report.2 The earlier recommendations evolved after concerns for the safety of HCWs exposed to HCV emerged at a meeting of the CDC’s Hospital Infection Control Practices Advisory Committee (HICPAC), at which some members criticized the CDC for not recommending any HCV postexposure follow-up for HCWs.
CDC officials had maintained that follow-up recommendations would be fairly futile due to lack of epidemiological data to support them, as well as no vaccination or effective postexposure prophylaxis. Nevertheless, recommendations were issued in the 1995 surveillance report to provide some guidance to hospitals grappling with the issue. (See related story in Hospital Employee Health, May 1996, pp. 49-53.)
Not much has changed in two years. As the 1997 recommendations note, "In the absence of 1) pre-exposure or postexposure prophylaxis, 2) recommendations that are unique for HCV to prevent HCV transmission to others, and 3) effective therapy for most persons with chronic hepatitis C, the overall health benefit associated with the identification of HCV infections in HCWs will be limited."
Despite the limitations, "it was felt there was some benefit to the individual health care worker to know what their outcome was," says Miriam Alter, PhD, chief of the epidemiology section of the CDC’s hepatitis branch. "There is a void in the information [regarding HCV prophylaxis] because there are recommendations for postexposure follow-up for other bloodborne pathogens."
Issues updated for MMWR
CDC officials, in collaboration with HICPAC, decided to publish what essentially are the 1995 recommendations "in a somewhat different form" in the recent MMWR because the hepatitis surveillance report "does not have the same broad readership that the MMWR has, and we also took this opportunity to update the issues as well," Alter says.
In its recommendations for hospitals, the CDC specifies that HCV exposure follow-up policies and procedures should at a minimum include:
• for the source, baseline testing for antibodies to HCV (anti-HCV);
• for the person exposed to an anti-HCV- positive source, baseline and follow-up (e.g. six-month) testing for anti-HCV and alanine aminotransferase activity;
• confirmation by supplemental anti-HCV testing of all anti-HCV results reported as repeatedly reactive by enzyme immunoassay (EIA);
• recommending against postexposure prophylaxis with immune globulin or antiviral agents (e.g., interferon);
• education of HCWs about the risk for and prevention of bloodborne infections, including hepatitis C, in occupational settings, with information routinely updated to ensure accuracy.
The guidelines state that HCWs who sustain percutaneous blood exposures from anti-HCV-positive patients have an average incidence of anti-HCV seroconversion of 1.8%, with a range of up to 7%. Another published report demonstrates that the risk of workers acquiring HCV infection via needlestick injury could be as high as 10.3%3. This compares to a range of between 6% and 30% for hepatitis B transmission, and "much less than 1%" for HIV, Alter says. One case report describes transmission of HCV from a blood splash to the conjunctiva.4
At least 85% of HCV infections become chronic, and chronic liver disease with persistently elevated liver enzymes develops in about 70% of HCV-infected people. Those with chronic disease are at risk for cirrhosis and primary hepatocellular carcinoma.1
The recommendations point out that no data exist to support the use of immune globulin for postexposure prophylaxis of hepatitis C. No assessments of antiviral agents such as alpha interferon have been made; the mechanisms of the effect of interferon in treating patients with HCV are poorly understood; and the drug is approved for treatment only of chronic hepatitis C. Therefore, the CDC does not recommend interferon for HCV postexposure prophylaxis regimens.
"There is no reason to assume that because you can give AZT [for HIV prophylaxis] that any antiviral is useful as a prophylactic rather than as a therapy," Alter says. "Given our lack of understanding of the mechanisms of the effect of interferon, there’s no reason to believe it would be effective as a prophylaxis prior to [HCV] infection."
PCR tests give faster results
Nevertheless, the recommendations note that interferon treatment begun early in the course of HCV infection is associated with a higher rate of resolved infection. Onset of HCV infection among HCWs postexposure could be detected earlier by measuring HCV RNA using polymerase chain reaction (PCR) instead of by measuring anti-HCV using EIA. However, PCR is not a licensed clinical assay, and result accuracy is "highly variable."
In addition, "there are no data indicating that treatment begun early during the course of chronic HCV infection is less effective than treatment begun during the acute phase of infection." Well-designed research protocols are needed to determine whether treatment of HCV infection is more beneficial in the acute phase than in the early chronic phase, the guidelines state.
The absence of postexposure prophylaxis raises at least six issues to be considered in establishing a protocol for following up HCWs occupationally exposed to HCV, the guidelines state:
1. Limited data about the occupational risk for transmission. Although needlestick exposure to infectious blood is a risk factor for HCV, data are limited or nonexistent about transmission risks associated with other types of occupational exposures. Therefore, meaningful estimates of HCV infection risks cannot be provided to HCWs who sustain those exposures.
2. Limitations of available serologic testing for detecting infection and determining infectivity. The average interval between exposure and seroconversion is eight to 10 weeks for commercially available EIAs that detect anti-HCV. In HCW populations, the rate of false positivity is at least 50%, necessitating the use of supplemental assays to assess the validity of repeatedly reactive EIA results. Currently, the only licensed supplemental test is the recombinant immunoblot assay (RIBA), Alter says.
However, approximately 5% of infections will go unidentified unless PCR is used to detect HCV RNA. PCR assays are not standardized, and each test costs approximately $200. Even then, both false-positive and false-negative results can occur.
3. Poorly defined risk for transmission by sexual and other exposures. While all anti-HCV-positive people should be considered potentially infectious, neither the presence of antibody nor the presence of HCV RNA is a direct measure of infectivity when inapparent parenteral or mucosal exposures occur. The efficiency of HCV transmission from exposure to infected sexual and household contacts is low, and the average rate of perinatal transmission is between 5% and 9%. Infection acquisition from breast milk has not been documented.
4. Limited benefit of therapy for chronic disease. Follow-up protocols allow eligible HCWs to be evaluated for chronic liver disease and treatment. Although interferon therapy is safe and effective for treatment of chronic HCV, sustained response rates generally are low (10% to 20% in the United States). Mild to moderate side effects require discontinuation of therapy in up to 15% of patients. No means have been identified to predict reliably which patients will respond to treatment and sustain long-term remission.
5. Cost of follow-up. The estimated annual cost of postexposure follow-up testing nationally is $2 million to $4 million, which Alter says is based on 2.5 million hospital-based HCWs with an exposure frequency of four to eight needlesticks per 100 person-years. "I applied that to how many anti-HCV-positive exposures would occur and then how many of those would actually result in seroconversion," she explains.
Estimated annual cost for each person who benefits from a six-month course of therapy is $200,000.
6. Medical and legal implications. Postexposure follow-up protocols will address workers’ concerns about their risk for HCV infection and possible disease outcomes, and will identify HCWs who become HCV-infected. This provides the opportunity for workers to be counseled about the risk for transmitting HCV to others and to be evaluated for development of chronic disease and for chronic disease therapy.
Counseling recommendations to prevent HCV transmission to others are:
• Anti-HCV-positive people should not donate blood, organs, tissues, or semen.
• Household contacts should not share toothbrushes and razors.
People with multiple sex partners should adopt safer-sex practices, including reducing the number of sex partners and using barriers (such as latex condoms) to prevent contact with body fluids.
People have called it six months of hell’
But Jon Rosenberg, MD, a medical epidemiologist for the California Department of Health Services’ division of communicable disease control in Berkeley, says counseling exposed HCWs also involves sensitivity to the emotional issues involved.
"A CDC recommendation is not the place you would expect to see considerations of emotional impact, but these things need to be brought out, perhaps in materials for those in health care facilities whose job it is to implement the recommendations," says Rosenberg, who monitors health care-acquired infections involving both HCWs and patients. "There is the uncertainty of waiting up to six months for antibody test results. People have called it six months of hell; it is a very emotionally disturbing period of time."
After an HCV exposure, workers often fear that seroconversion could damage or destroy their career and adversely affect their family life. Some workers might not seek testing or follow-up because they do not want to know for sure if they are infected.
"If there is no treatment for acute infection, people won’t want to come in for follow-up if they are only going to be tested and told if they are positive," says Rosenberg, who advocates a major study of HCWs to determine the effect of interferon in acute-phase treatment of HCV.
"If a study were done with offering interferon after PCR shows infection, then [HCWs] will want to come in for postexposure follow-up," he says. "As it is now, you counsel, but what are you counseling people on? You can give emotional support, but they have to make decisions on what they will do about their lives."
Rosenberg says even though the CDC does not recommend interferon for postexposure prophylaxis, there still was "a big leap forward" from 1995 guidelines. That came just in the fact that the CDC simply referred to the possibility that interferon treatment begun early in the course of infection might result in a higher rate of resolved infections.
"The CDC is by necessity data-bound," he states. "Some would argue that there’s a reasonable rationale for early treatment with interferon, but the CDC points out the problems with that. Not only has no one studied it, but in order to diagnose early infection you have to do a molecular assay, and no molecular assays are clearly established, clinically available, and FDA-approved for that use."
With an 85% risk of chronic hepatitis C, infected HCWs face "a pretty abysmal future," he adds. The CDC recommendations encourage hospitals to establish postexposure policies and procedures, and they provide "an honest, accurate portrayal of what we know and don’t know" about interferon treatment.
References
1. Centers for Disease Control and Prevention. Recom men dations for follow-up of health-care workers after occupational exposure to hepatitis C virus. MMWR 1997; 46:603-606.
2. Centers for Disease Control and Prevention. Risk of acquiring hepatitis C for health care workers and recommendations for prophylaxis and follow-up after occupational exposure. Hepatitis Surveillance Report No. 56. Atlanta: U.S. Department of Health and Human Services, Public Health Service; 1995, pp. 3-6.
3. Mitsui T, Iwano K, Masuko K, et al. Hepatitis C virus infection in medical personnel after needlestick accident. Hepatology 1992; 16:1109-1114.
4. 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.
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