Introduction and objectives: Epidemiological data on symptomatic HCV infection in Poland has shown that its prevalence among health care workers (HCWs) may exceed the prevalence notified among general population. Since such epidemiological situation would be similar to the increased prevalence of HBV infection among HCWs before anti-hepatitis B vaccine era, a seroprevalence study on HCV infection and immunity to HBV was performed in the group of volunteering HCWs.
Material and methods: All the persons employed as HCWs in the two largest clinical hospitals in Warsaw were invited to participate in the study. They voluntarily gave a sample of blood for serological examination and were asked to fill-in a questionnaire containing questions relevant to the possible routes of infection, period of employment, and in part also to their life style. Both were done anonymously and in the unlinked manner. The activity of aminotransferases has also been determined in all the samples.
Results: 961 serum samples were collected from HCWs employed in both hospitals. Anti-HCV were detectable in 16 out of 961 sera (1.7%). HCV RNA was detected in 3 out of these 16 (19%) sera; in 2 serum samples genotype 2, in 1--genotype 1b HCV. Anti-HBs were detected in 943 out of 961 (98.1%) sera. Anti-HBc (total) were detectable in 151 out of 961 (15.7%) sera. Out of 151 sera with anti-HBc in 149 (98.7%) samples anti-HBs were also detected. HBV DNA was detected in 6 (4%) samples out of 151 sera containing anti-HBc. While the prevalence of asymptomatic HCV infection among HCWs is similar to that seen in general population in Poland, the 15.7% prevalence of anti-HBc exceeded almost three times the percentage found in another study.
Conclusions: Since vaccination of health care personnel against HBV is at present obligatory, a large percentage of anti-HBs positive persons indicates for a high rate of immune response to vaccination. However, it seems that the presence of anti-HBs may not always be taken as indicating for immunity to HBV, but in some persons it may mask occult HBV infection. Since a younger population is immune to HBV infection due to universal vaccination of newborns and catch-up vaccination program for teenagers, older generations of HCWs may constitute a risk group for occult HBV infection.