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Prevalence of hepatitis C antibodies among healthcare workers of two teaching hospitals. Who is at risk?

BMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7075.179 (Published 18 January 1997) Cite this as: BMJ 1997;314:179
  1. Keith R Neal, Senior lecturer in communicable disease controla (keith.neal{at}nottingham.ac.uk),
  2. John Dornan, Consultant physician in occupational medicineb,
  3. Will L Irving, Reader in medical virologyc
  1. a Department of Public Health Medicine, University of Nottingham NG7 2UH
  2. b Nottingham Occupational Health, Queen's Medical Centre, Nottingham NG7 2UH
  3. c Department of Microbiology, University of Nottingham, Nottingham NG7 2UH
  1. Correspondence to: Dr Neal
  • Accepted 6 September 1996

Introduction

Epidemiological evidence suggests that healthcare workers are at an increased risk of hepatitis C infection,1 and episodes of hepatitis C infection after needlestick incidents2 and transmission of the virus in hospitals in developed countries have also been reported.3 Studies of prevalence in healthcare workers so far published4 have neither supported nor repudiated the increased risk suggested by the epidemiological evidence. With increasing concern about the risks of transmission of viruses such as hepatitis and HIV between patients and healthcare workers,5 it is important that the real risk, if any, is measured. We report the results of a study to measure the prevalence of hepatitis C antibodies in healthcare workers whose hepatitis B status was being assessed.

Patients, methods, and results

Blood samples taken from Nottingham hospital staff for measuring hepatitis B surface antibody levels from January 1994 to October 1995 were identified from the virology computer and matched to data from the occupational health database by record linkage using surname, first name, date of birth, and date of blood test. The database included main occupational group, age, sex, and place and type of work. A unique study number was attached to the combined data set and all identifying features were removed. Microsoft Access 2.0 was used as the database and for record linkage and spss for Windows for the statistical analyses.

A total of 1949 samples were retrieved and placed into tubes with only the unique study number for identification. Hepatitis C antibody testing was performed using a second generation ELISA (enzyme linked immunoasorbent assay, UBI) according to the manufacturer's instructions. All samples showing reactivity in this assay were then tested using a third generation ELISA (Ortho). Four samples positive in both ELISAs were identified from 1949 samples, a rate of 2.05 per 1000 (95% confidence interval 0.55 to 5.2; table 1) The number of positive results was too small for subgroup analysis.

Table 1

Staff groups, by age and sex, of health care workers tested (number positive) for hepatitis C antibodies

View this table:

Comment

Our results show that the prevalence of hepatitis C antibodies in healthcare workers is low. The use of blood samples from staff who had already been identified as most at risk of infection by a blood borne virus emphasises this low risk: many of the staff we included in this study had been vaccinated as part of the original targeted hepatitis B vaccine programme and had blood taken for hepatitis B surface antibody titres before their booster.

A case-control study of local blood donors showed a rate of hepatitis C infection of 1 in 1350 (0.7 per 1000) and an increased risk in healthcare workers, with a relative risk of 2.8.1 Our seroprevalence in high risk healthcare workers was 2.05 per 1000, 2.9-fold higher than in blood donors, a figure similar to that in the case-control study. Nevertheless, although blood donors are the largest group for whom prevalence data exist, they are self selected individuals with a below average risk for hepatitis C infection.

There are few studies of the prevalence of hepatitis C infection in health care workers in countries with a low prevalence of the infection, but one study in London showed a prevalence consistent with ours–of 2.8 per 1000.4 A combination of this study and our results gives a prevalence of 2.3 per 1000 (0.9 to 4.8 per 1000), 1 in 429 healthcare workers.

Because the study was anonymous we could not identify other possible risk factors for the four people with hepatitis C infection, such as a previous blood transfusion or a history of injecting drug use. The real rate of occupationally acquired hepatitis C infection might be even lower. In conclusion, our results show that the prevalence of hepatitis C infection among UK healthcare workers is low and until risks of infection to patients have been better documented routine testing of healthcare workers performing exposure prone activities is not warranted.

Acknowledgments

Funding: Wellcome Trust.

Conflict of interest: None.

References

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