Intrafamilial transmission of hepatitis C virus: infection of the father predicts the risk of perinatal transmission.

The aims of the present study were to evaluate in a cohort of mothers infected with hepatitis C virus (HCV) the prevalence of HCV infection of their sexual partners, the influence of infection of the partners on perinatal transmission, and whether this influence is mediated by other well known risk factors for perinatal transmission. Forty-nine consecutive mothers infected with HCV who transmitted infection to their offspring and, as a control group, 557 consecutive mothers infected with HCV who did not transmit infection, together with their children and the fathers of the children who were also the sexual partners of the mothers were evaluated. History of intravenous drug use was significantly more frequent in women with partners infected with HCV than in women with partners not infected [115/180 (63.9%) vs. 87/401 (21.7%); relative risk (RR): 6.38, 95% confidence intervals (CI): 4.34-9.39, P < 10(-3)]. HCV infection was more frequent in the partners of mothers who transmitted perinatally HCV [23/49 (46.9%) vs. 174/557 (31.2%); RR: 1.95, 95%CI: 1.08-3.51, P = 0.03]. Multivariate analysis demonstrated that paternal HCV infection is not a risk factor per se for perinatal HCV transmission, but its role is dependent on maternal intravenous drug use [adjusted RR: 1.23 (95%CI: 0.44-3.39, P = 0.6)]. In conclusion, the present study shows that partners of mothers infected with HCV with a history of intravenous drug use were at a higher risk of HCV infection. HCV infection of the father seems to be associated with perinatal transmission but this relationship is dependent on maternal history of intravenous drug use.