Risk factors for intrafamilial spread of hepatitis B in northeastern Bosnia and Herzegovina.

<b>Background: </b> Accurate estimations of hepatitis B virus transmission risk for any region in Bosnia and Herzegovina are not clearly established. We aimed to determine levels of risk associated with intrafamilial transmission of hepatitis B infection within families in our region. <b> Patients and Methods: </b> Family members of 81 chronic carriers of hepatitis B surface antigen (>6 months positive and considered as index case) were tested for hepatitis B markers. For family members, we recorded their age, sex, and family relationship to the index case, and vaccination status. <b> Results: </b> The proportion of HBsAg positive family members was 25/207 (12.1&#x0025;), while the proportion of family members with evidence of exposure to HBV was 80/207 (38.6&#x0025;). Only 17/207 (8.2&#x0025;) family members had evi--dence of past HBV vaccination. Age was found to be a significant predictor of HBV exposure of family members (odds ratio 1.05, 95&#x0025; CI 1.03-1.07, P&#60; .001). In a multivariate analysis, HBsAg positivity was associated with a female index case (odds ratio 11.31, 95&#x0025; CI 3.73-34.32, P&#60; .001), HBeAg positivity in the index case (odds ratio 5.56, 95&#x0025; CI 1.80-17.23, P&#60; .005) and being a mother of the index case (odds ratio 9.82, 95&#x0025; CI 2.43-39.68,P&#60; .005). A female index case (odds ratio 4.87, 95&#x0025; CI 2.21-10.72, P&#60; .001), HBeAg positivity in the index case (odds ratio 3.22, 95&#x0025; CI 1.15-9.00, P&#60; .05) and being a mother of the index case (odds ratio 3.72, 95&#x0025; CI 1.19-11.64, P&#60; .05) were also risk factors for HBV exposure among family members. The combination of HBeAg positivity and female index case was a significant predictor for HBsAg positivity of family members (odds ratio 70.39, 95&#x0025; CI 8.20-604.61, P&#60; .001). <b> Conclusions: </b> Children of HBeAg positive mothers are at highest risk for becoming chronic carriers them--selves and generally, the combination of female sex and HBeAg positivity dramatically increases the chances of HBV transmission within the family