 |
Notice to Readers
Recommendations for Follow-Up of Health-Care Workers After
Occupational Exposure to Hepatitis C Virus
Hepatitis C virus (HCV) infection is a major cause of chronic
liver disease in the United States and worldwide. At least 85% of
persons with HCV infection become chronically infected, and chronic
liver disease with persistently elevated liver enzymes develops in
approximately 70% of all HCV-infected persons (1). Persons with
chronic hepatitis C are at risk for cirrhosis and primary
hepatocellular carcinoma. Most HCV transmission is associated with
direct percutaneous exposure to blood. Health-care workers (HCWs)
are at occupational risk for acquiring this viral infection.
However, no vaccine is available to prevent hepatitis C, and immune
globulin is not recommended for postexposure prophylaxis.
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 public health benefit
associated with the identification of HCV infections in HCWs will
be limited. However, to address individual workers' concerns about
risk and outcome, CDC, in collaboration with the Hospital Infection
Control Practices Advisory Committee, recommends that individual
health-care institutions consider implementing policies and
procedures for follow-up for HCV infection after percutaneous or
permucosal exposures to blood (2). At a minimum, such policies
should include
for the source, baseline testing for antibody to HCV (anti-HCV);
for the person exposed to an anti-HCV-positive source, baseline
and follow-up (e.g., 6-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); and
education of HCWs about the risk for and prevention of
bloodborne infections, including hepatitis C, in occupational
settings, with the information routinely updated to ensure
accuracy.
Follow-up studies of HCWs who sustained a percutaneous
exposure to blood from an anti-HCV-positive patient have reported
an average incidence of anti-HCV seroconversion after unintentional
needlesticks or sharps exposures of 1.8% (range: 0-7%) (1-5). A
seroconversion rate of 6% was documented in the United States (4);
in Japan, the incidence was 10% based on detection of HCV RNA by
PCR (5). Although these follow-up studies have not documented
transmission associated with mucous membrane or nonintact skin
exposures, the transmission of HCV from a blood splash to the
conjunctiva was described in one case report (6).
In February 1994, the Advisory Committee on Immunization
Practices reviewed data about the prevention of HCV infection with
immune globulin and concluded that there was no basis for
supporting the use of immune globulin for postexposure prophylaxis
of hepatitis C. There have been no assessments of the prevention of
HCV infection with antiviral agents (e.g., alpha interferon), and
the mechanisms of the effect of interferon in treating patients
with hepatitis C are poorly understood; an established infection
may need to be present for interferon to be an effective treatment
(7). Interferon must be administered by injection and may cause
severe side effects. Based on these considerations, postexposure
prophylaxis regimens with antiviral agents for HCV infection are
not recommended.
Several studies suggest that interferon treatment begun early
in the course of HCV infection is associated with a higher rate of
resolved infection. Among HCWs in the postexposure period, onset of
HCV infection could be detected earlier by measuring HCV RNA using
polymerase chain reaction (PCR) rather than by measuring anti-HCV
using EIA. However, PCR is not a licensed assay, and the accuracy
of the results are 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. Furthermore, alpha interferon is approved
for the treatment only of chronic hepatitis C. Determination of
whether treatment of HCV infection is more beneficial in the acute
phase than in the early chronic phase will require evaluation with
well-designed research protocols.
In the absence of postexposure prophylaxis, at least six
issues need to be considered in defining a protocol for the
follow-up of HCWs occupationally exposed to HCV:
Limited data about the occupational risk for transmission.
Although needlestick exposure to infectious blood is a risk
factor
for hepatitis C and this risk is intermediate between that of
hepatitis B virus and human immunodeficiency virus, data are
limited or nonexistent about the risk for transmission
associated
with other types of occupational exposures. Thus, meaningful
estimates of the risk for HCV infection cannot be provided to
HCWs
who sustain such exposures.
Limitations of available serologic testing for detecting
infection and determining infectivity. Testing methods readily
available in the clinical setting are subject to some
limitations.
For the commercially available EIAs that detect anti-HCV, the
average interval between exposure and seroconversion is 8-10
weeks.
In many populations, including HCWs, the rate of false
positivity
for anti-HCV is at least 50%, and supplemental assays always
should
be used to assess the validity of repeatedly reactive EIA
results.
Approximately 5% of infections will not be detected unless PCR
is
used to detect HCV RNA. Although such assays are available from
several commercial laboratories for research use, they are not
standardized, and each test costs approximately $200. Both
false-positive and false-negative results can occur as a
consequence of improper handling and storage or contamination of
test samples. In addition, the detection of HCV RNA may be
intermittent, and a single negative PCR test result is not
conclusive.
Poorly defined risk for transmission by sexual and other
exposures. All anti-HCV-positive persons should be considered
potentially infectious; however, neither the presence of
antibody
nor the presence of HCV RNA is a direct measure of infectivity
in
settings where inapparent parenteral or mucosal exposures occur.
Although epidemiologic studies have implicated exposure to
infected
sexual and household contacts as well as to multiple sex
partners
in the transmission of HCV, the efficiency of transmission from
these exposures is low (1). Studies of infants born to
anti-HCV-positive
mothers have documented an average rate of perinatal
transmission of 5%, increasing to 9% among infants born to
mothers
who were HCV RNA-positive at the infant's birth (8). Acquisition
of
HCV infection from breast milk has not been documented, and in
studies of breastfeeding among infants born to HCV-infected
women,
the average rate of infection was 4% in both breastfed and
bottle-fed infants (8).
Limited benefit of therapy for chronic disease. One benefit from
a follow-up protocol is the opportunity for eligible HCWs to
seek
evaluation for chronic liver disease and treatment. Although
alpha
interferon therapy is safe and effective for the treatment of
chronic hepatitis C (9), sustained response rates generally are
low
(10%-20% in the United States); the occurrence of mild to
moderate
side effects in most patients has required discontinuation of
therapy in up to 15% of patients. No clinical, demographic,
serum
biochemical, serologic, or histologic features have been
identified
that reliably predict which patients will respond to treatment
and
sustain a long-term remission.
Cost of follow-up. The estimated annual cost of providing
postexposure follow-up testing nationally is $2-$4 million; the
estimated cost for each person for a 6-month course of therapy
is
$200,000 (CDC, unpublished data, 1995).
Medical and legal implications. A postexposure follow-up
protocol will address individual workers' concerns about their
risk
for HCV infection and possible disease outcomes, and identify
those
HCWs who become infected with HCV; this information provides
HCWs
with the opportunity to be counseled about their risk for
transmitting HCV to others and to be evaluated for development
of
chronic disease, and, if eligible, for therapy for chronic
hepatitis C.
Counseling recommendations to prevent transmission of HCV to
others (10) are that 1) persons who are anti-HCV-positive should
refrain from donating blood, organs, tissues, or semen, and 2)
household contacts should not share toothbrushes and razors.
However, there are neither recommendations against pregnancy or
breastfeeding nor recommendations for changes in sexual practices
among HCV-infected persons with a steady partner. Although HCV
sometimes can be transmitted from persons with chronic disease to
their steady sex partners, the risk for transmission is low despite
long-term, ongoing sexual activity. Infected persons should be
informed of the potential risk for sexual transmission to assist in
decision-making about precautions. Persons with multiple sex
partners should adopt safer sex practices, including reducing the
number of sex partners and using barriers (e.g., latex condoms) to
prevent contact with body fluids.
Reported by: Hepatitis Br, Div of Viral and Rickettsial Diseases,
National Center for Infectious Diseases, CDC.
References
Alter MJ. Epidemiology of hepatitis C in the West. Semin Liver
Dis 1995;15:5-14.
CDC. 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,
Georgia:
US Department of Health and Human Services, Public Health
Service,
1995:3-6.
Puro V, Petrosillo N, Ippolito G, Italian Study Group on
Occupational Risk of HIV and Other Bloodborne Infections. Risk
of
hepatitis C seroconversion after occupational exposures in
health
care workers. Am J Infect Control 1995;23:273-7.
Lanphear BP, Linnemann CC Jr, Cannon CG, DeRonde MM, Pendy L,
Kerley LM. Hepatitis C virus infection in health care workers:
risk
of exposure and infection. Infect Control Hosp Epidemiol
1994;15:745-50.
Mitsui T, Iwano K, Masuko K, et al. Hepatitis C virus infection
in medical personnel after needlestick accident. Hepatology
1992;16:1109-14.
Sartori M, La Terra G, Aglietta M, Manzin A, Navino C, Verzetti
G. Transmission of hepatitis C via blood splash into conjunctiva. Scand J Infect Dis 1993;25:270-1.
Peters M, Davis GL, Dooley JS, Hoofnagle JH. The interferon system in acute and chronic viral hepatitis. Prog Liver Dis
1986;8:453-67.
Mast EE, Alter MJ. Hepatitis C. Semin Ped Infect Dis
1997;8:17-22.
Hoofnagle JH, Di Bisceglie AM. Drug therapy: the treatment of chronic viral hepatitis. N Engl J Med 1997;336:347-56.
CDC. Public Health Service inter-agency guidelines for screening donors of blood, plasma, organs, tissues, and semen
for
evidence of hepatitis B and hepatitis C. MMWR 1991;40(no.
RR-4):1-17.
Disclaimer
All MMWR HTML versions of articles are electronic conversions from ASCII text into HTML. This conversion may have resulted in character translation or format errors in the HTML version. Users should not rely on this HTML document, but are referred to the electronic PDF version and/or the original MMWR paper copy for the official text, figures, and tables. An original paper copy of this issue can be obtained from the Superintendent of Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-1800. Contact GPO for current prices. **Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.Page converted: 09/19/98
|
|
