Health-care workers are known to be at risk from occupational
transmission of blood-borne viruses, including hepatitis C. There
may be serious implications following infection with hepatitis C
including possible transmission to patients.
We determined the prevalence of hepatitis C virus (Hepatitis C Virus) antibodies
among health-care workers at risk of occupational contact with
blood and body fluids and among source patients in reported
blood-exposure incidents. Anonymised stored blood samples from
health-care workers immunised against hepatitis B virus since 1991
(n = 1053) and blood samples from source patients in needlestick
injuries (retrospective and prospective) since 1989 (n = 373) were
analysed. 3 (0.28%) of the serum samples from health-care workers
were found to be anti-Hepatitis C Virus-positive. 17 (8-5%) of 200 source
patients tested retrospectively between January 1989 and January
1992, and 24 (13.9%) of 173 source patients tested prospectively
between January 1992 and June 1993 were anti-Hepatitis C Virus-positive. During
the second period, 15 (10.6%) of 142 source patients tested for
human immunodeficiency virus (HIV) were positive and 7 (3.8%) of
184 source patients tested for hepatitis B surface antigen were
positive. 6 of 24 (25%) Hepatitis C Virus-infected patients were diagnosed only
after the incident; for hepatitis B, 2 (33%) of patients were
diagnosed after the incident, and for HIV all patients were
The seroprevalence of Hepatitis C Virus among these health-care workers is no
higher than that reported in blood donors. This suggests that
there has not been significant occupational transmission of Hepatitis C Virus to
these health-care workers despite the high prevalence of Hepatitis C Virus
(often covert) among source patients in reported blood exposure in
the same hospital.
Lancet 1994; 343:1618-20
Health-care workers are at risk of infection by blood-borne
viruses through needlestick injuries and other blood-exposures.
Transmission of hepatitis virus (Hepatitis C Virus) after
accidental blood inoculation has been recorded and several studies
on the occupational risk of Hepatitis C Virus infection have been
Occupational infection with Hepatitis C Virus may have serious long-term
implications: establishment of a carrier state, chronic liver
disease, and possible transmission to patients. Understandably,
health-care workers are anxious about the possibility of Hepatitis C Virus
infection when a needlestick injury occurs. We studied the
prevalence of Hepatitis C Virus antibodies among health-care workers with direct
and indirect clinical contact. In the same hospital, we assessed
the potential for occupational transmission of Hepatitis C Virus infection by
measuring its seroprevalence among patients involved in reported
The Occupational Health Unit at The Royal Free NHS Trust Hospital,
London, UK, has well-established protocols for hepatitis B (HBV)
immunisation of staff
and for managing needlestick injuries? Staff who are at risk of
blood exposures at work (doctors, nurses, and laboratory and
ancillary staff) are offered HBV immunisation with subsequent
testing of antibody response. Several thousand staff have been
immunised and many of these have had frozen serum samples stored.
This allowed us to investigate the prevalence of Hepatitis C Virus by a
second-generation enzyme immunoassay antibody test (Ortho
Diagnostics, High Wycombe, UK) and supplementary tests with Ortho
immunoblot assay (RIBA II) on any repeatedly reactive samples.
Individuals to be tested were those on a computer database of
staff immunised against HBV and tested for response since January
1991, stratified by age (< 24 years, 25 to 39 years, and > 40
years); and two occupational groups, those with direct clinical
exposure (medical and nursing staff) and those with indirect
clinical exposure (laboratory and ancillary staff). There were
1053 stored serum samples available; aliquots were decanted into
unlabelled containers, coded for age group and occupational group,
and randomly numbered. These anonymous samples were then tested
for Hepatitis C Virus antibodies.
Aliquots of all available 200 source patients in reported
blood-exposure incidents January 1986 to December 1991 with stored
serum samples were decanted into unlabelled containers and tested
anonymously for hepatitis C antibodies.
From January 1992, identified source patients in blood exposure
incidents have been routinely asked for consent to be tested for
Hepatitis C Virus antibodies in addition to our previous practice of requesting
testing for HIV antibodies and HBV surface antigen (HBsAg). 245
source patients were identified up to June 1993, of whom 184 were
tested for HBsAg, 142 for HIV antibodies, and 173 for antibodies
to Hepatitis C Virus. If any sample was found to be positive for Hepatitis C Virus antibodies,
supplementary tests were undertaken and the staff member involved
in the incident was offered follow-up tests for serum liver
enzymes and hepatitis C antibodies for one year.
The overall seroprevalence of Hepatitis C Virus antibodies amongst 1053 health
care workers was 0.28% (table 1). There appeared to be a trend for
hepatitis C antibodies to be found more frequently in older age
groups, but the number of positive samples (3)
was very small. 17 (8.5%) of the 200 source patients involved in
blood exposures from January 1989 to January 1992 were Hepatitis C Virus-antibody
positive. From January 1992 to June 1993, 24 (13.9%) of 173 source
patients tested were Hepatitis C Virus-antibody positive (table 2). In addition,
15 (10.6%) of 143 source patients were HIV-antibody positive and 6
(3.8%) of 184 source patients were HBsAg-positive (table 2).
Table 2 also shows that all 15 source patients who were
HIV-positive had been diagnosed before the needlestick injury. In
contrast, 2 of 6 (33%) patients infected with HBV and 6 of 24
(25%) infected with Hepatitis C Virus were diagnosed only after the incident.
None of the health-care workers followed up after the 24 Hepatitis C Virus
antibody-positive blood exposures since January 1992 has
seroconverted for Hepatitis C Virus, nor have there been any HBV or HIV
seroconversions in our hospital following infected blood exposures
An increased prevalence of markers of HBV infection was recognised
among health-care workers before widespread immunisation.
Epidemiological and experimental studies have indicated that Hepatitis C Virus
can be transmitted by the parenteral route, and it is known that
infected blood transfusions are an important route of
There have been several reports of Hepatitis C Virus transmission following
needlestick injuries and one report of transmission by a human
A study of New York dentists
found that 2% bad antibodies to Hepatitis C Virus compared with
0'1% among controls. A study of German hospital staff
reported a seroprevalence of 0.58% compared with 0.24% among
blood-donor controls. In contrast, a UK study of dental surgeons
reported that none had antibodies to Hepatitis C Virus compared with a 0.3% seroprevalence among local blood donor controls.
A recent prospective study of hospital employees estimated the
risk of Hepatitis C Virus transmission to be 4% after needlestick
exposure to anti-Hepatitis C Virus-positive blood.
A Japanese study found the risk of transmission from a single needlestick
accident with Hepatitis C Virus RNA-positive blood to be 10%.
The apparent difference was most likely due to the use of
different markers for Hepatitis C Virus infection in the two studies. The
present study shows that the seroprevalence of Hepatitis C Virus
infection among health care workers in potential contact with
blood in our hospital is no higher than the 0.3% previously
reported in UK blood donors.
There is presently a seroprevalence rate for Hepatitis C Virus of
0.07% in new blood donors in north London
and our figure of 0.28% is somewhat higher. Nonetheless, seroprevalence amongst staff is low. This is encouraging and
suggests that there has not been significant occupational
transmission of hepatitis C to these workers in the past.
The high seroprevalence of Hepatitis C Virus in source patients probably
reflects the type of patients in the hospital, which has a large
liver unit, and renal dialysis and haemophilia units. Incidents
involving patients known to be infected with a blood-borne virus
may also be more likely to be reported. Recent guidance concerning
occupational exposure to Hepatitis C Virus
states that routine Hepatitis C Virus-antibody testing from identifiable source
patients of unknown Hepatitis C Virus status is presently not justified.
However, in this study, 25%of source patients infected with Hepatitis C Virus
were identified as such only after the blood exposure incident
(table 2). Therefore, if the resources are available, we suggest
it is appropriate to test--with consent--all source patients of
unknown Hepatitis C Virus status. In this way, the health-care worker involved
in the blood exposure incident can be counselled as early as
possible about the risk of transmission and either reassured or
given informed advice about follow-up procedures.
The results of this study indicate that there is a continuing risk
of exposure to blood-borne viruses from blood exposure incidents
in this hospital. The fact that Hepatitis C Virus and HBV infection in a number
of patients in blood exposure incidents was not known at the time
of the incident (see table 2) argues in favour of universal
precautions for blood and body fluids,ts which is the policy in
our hospital. The Hepatitis C Virus seroprevalence among staff should not lead
to complacency. Efforts to reduce blood exposures are important as
the best way to reduce the risk of occupational transmission of
HIV, HBV, and Hepatitis C Virus.
We thank Toyin Shobande and Chris Gooch for their help with this
study, and the Medical Research Council for financial support.
Table 1: Prevalence of hepatitis C antibodies in health-care
workers with clinical contact
Age (years) Clinical exposure group Total
</=24 0/246 (0%) 0/84 (0%) 0/330 (0%)
25-39 1/186 (054%) 0/174 (0%) 1/360 (028%)
>/=40 0/184 (0%) 2/179 (1-12%) 2/363 (0.55%)
Total 1/616 (016%) 2/437 (0.46%) 3/1053 (0.28%)
Table 2: Results of testing for blood-borne viruses in
identified source patients In reported blood exposure incidents
(January 1992-June 1993)
Marker Serological status of patient
Tested before Incident Tested after Total tested
No No No No No No
tested positive tested positive tested positive
HBsAg 77 4 107 2 184 6
HIVAbS 53 15 90 0 143 15
HCVAbs 54 18 119 6 173 24
There are 245 identified source patients in 285 blood exposure
incidents reported January 1992 to June 1993. Reasons for not
testing source patients after the incident, despite a policy of
requesting testing in each patient (unless previously tested),
have been described elsewhere. HBSAg= hepatitis 8 surface antipen,
HIVAbs = human immunodeficiency virus antibodies, HCVAbS =
hepatitis C virus antibodies.
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By Jane Zuckerman, Gillian Clewlay, Paul Griffiths and Anne
Occupational Health Unit (J Zuckerman MD, A Cockcroft FRCP), and
Department of Virology, Division of Communicable DIsease, Royal
Free NHS Trust and Royal Free Hospital School of Medicine, London,
UK (G Clewely esc, Prof P Griffiths MRCPath
Correspondence to: Jane Zuckerman, Occupational Health Unit, Royal
Free Hospital of Medicine, 5 Rosslyn Hill, London NW3 5UL, UK