Excluding hepatitis C virus (HCV) infection by serology in young infants of HCV-infected mothers.

Aim: To identify the age at which HCV infection can be accurately excluded by serology in young children born to HCV-infected mothers and to determine an appropriate schedule of antibody testing, most informative to clinical practice.

Methods: Children born to HCV-infected mothers were followed in centres of the European Paediatric HCV Network. Turnbull survival analysis techniques were used to estimate the age at which HCV-uninfected children will lose maternally acquired HCV antibodies. Factors associated with age at antibody loss were assessed in logistic regression.

Results: In 1104 children followed from birth and later confirmed to be HCV uninfected, an estimated 57% will have lost passively acquired HCV antibodies before 6 mo of age and an estimated 95% by 12 mo. Maternal HCV viraemia antenatally was associated with later, and maternal HIV-HCV co-infection with earlier loss of antibody. Actual antibody testing of uninfected children at 12 mo identified 82% of those tested to be anti-HCV negative.

Conclusions: Serological confirmation of HCV uninfection remains necessary given the uncertainty in the specificity of virological tests. These results suggest that, in most children, HCV infection can be ruled out with serological testing at an earlier age than previously thought, and that nearly all children born to HCV-infected mothers will have lost passively acquired maternal antibodies by 1 y of age. Antibody loss was significantly later among children born to HCV viraemic mothers. The earlier loss of HCV antibodies in children born to HIV co-infected mothers may be due to HIV treatment.