Mother-to-infant transmission of hepatitis C virus.

Since the programme of the hepatitis B virus vaccination started, hepatitis C virus has become the most significant cause of chronic liver disease of infectious aetiology in paediatric age. After the introduction of hepatitis C virus screening of blood units, vertical transmission seems to now be the most common route of hepatitis C virus infection in children. According to studies on infants born to anti-hepatitis C virus positive women, the rate of mother-to-infant transmission is about 5% when the mother is anti-hepatitis C virus positive and anti-HIV negative, but the risk is three-five times higher when the mother is coinfected with HIV. Both viral and host-related factors are of importance as risk factors in vertical hepatitis C virus transmission. Among the first, only viral load has been demonstrated by some authors as a relevant risk factor while genotype seems not to be influent. The importance of quasispecies has been hypothesized but not yet clarified. Among host-related factors, beyond maternal HIV coinfection, maternal drug abuse has certainly an important role. Other factors such as breast feeding and vaginal delivery do not seem to influence the rate of vertical transmission. Progression to chronicity occurs in the majority of perinatally infected children, although hepatitis C virus associated liver disease is usually mild throughout infancy and childhood.