Significant proportion of acute hepatitis B in Poland in 2010–2014 attributed to hospital transmission: combining surveillance and public registries data

BACKGROUND: Efficient control of acute hepatitis B requires identification of current transmission routes. Countries in Central-Eastern Europe including Poland attribute an important fraction of cases to nosocomial transmission, as opposed to Western European countries. However, due to possible multiple exposures during the incubation time such assignment may be debatable. This study aimed at assessing of most affected groups and current transmission pattern of acute hepatitis B. METHODS: We investigated exposures reported by acute hepatitis B cases notified to routine surveillance system in Poland in 2010–2014 in comparison to data on hospitalization rates in general population. RESULTS: Hospitalization during incubation time significantly increased the risk of HBV infection (RR 3.13, 95%CI 2.58–3.80). Overall hospitalization population attributable risk (PAR%) was 25.7% (95% CI 20.3%–31.1%) as compared to 35% of acute cases assigned to hospital transmission in surveillance database. PAR% increased from 9.5% (1.12%–17.8%) in the age group 25–34 to 41.1% (28.2% - 53.9%) among those 65 +. In addition, cases < 40 more frequently than the older ones reported history of injecting drugs and risky sexual contacts (25% vs 5%). 27% of men < 40 did not report any exposure at all, drawing attention to possible underreporting of risk behaviors. CONCLUSIONS: The distribution of probable transmission routes differed by age and gender. Further improvement of HBV control requires better coverage of vaccination in risk groups but also strengthening the blood-borne infections control in hospitals.