Intrafamilial transmission of hepatitis B in Tuzla region of Bosnia and Herzegovina

Objective To determine (i) the prevalence of HBV infection in families of confirmed chronic carriers, (ii) possible routes of transmission and risk factors for the intrafamilial transmission, (iii) vaccination rate among family members of chronic carriers and (iv) family members with highest risk for infection. Methods A total of 172 family members of 67 hepatitis B surface antigen chronic carriers were tested for hepatitis B markers; 716 first-time blood donors from the same area were used as controls. Results Prevalence of hepatitis B surface antigen was higher (P<0.001) among family members of index cases (12.2%; 21/172) than among controls (3.6%; 26/716) with relative risk of 3.3 (95% confidence Intervals=1.9–5.8; P<0.05). Rate of exposure among family members was 37.8% (65/172); only 8.7% (15/172) had been vaccinated for hepatitis B virus. Difference (P<0.001) in exposure existed among family members; exposure increased with age (ρs=0.34; P<0.001). Prevalences of hepatitis B surface antigen positivity and hepatitis B virus exposure were higher among parents of index cases (P<0.005) and among offspring of female index cases (P<0.001). There were more (P<0.001) hepatitis B surface antigen-positive family members among those with mother–children relationship with index case (13/31; 41.9%) than among those with father–children (19/85; 22.4%) and horizontal (siblings and spouses) relationship (2/56; 3.6%). Significantly more (P<0.001) hepatitis B surface antigen-positive and hepatitis B virus-exposed offspring were found in families where only mother was hepatitis B surface antigen positive. Among family members of HBeAg-positive cases more hepatitis B surface antigen-positive cases and hepatitis B virus-exposed cases have been found (P<0.001). Combination of HBeAg positivity and female sex of index case significantly increased risk for chronic carriage among family members (relative risk=24.06; 95% confidence interval=8.88–65.21; P<0.05). Conclusion In the area studied, both horizontal and vertical transmission exists, but maternal route is predominant. Female sex, HBeAg positivity of index carrier and presence of hepatitis B surface antigen-positive mother inside family increased risk for hepatitis B surface antigen positivity and exposure among family members. Vaccination rate of family members of index cases is alarmingly low.