Objectives: To study viral persistence and antibody responses after hepatitis G virus (HGV) infection in children of various ages.

Study design: We performed an enzyme immunoassay for antibodies to E2 protein (anti-E2) of HGV and reverse-transcription polymerase chain reaction assay for HGV RNA on serum samples.

Results: Of 28 infants born to HGV RNA–positive mothers, 17 were found to be positive for HGV RNA. None were positive for anti-E2. All 17 infected infants continued to have viremia except 1 who converted to HGV RNA–negative status at 24 months. Six infants had mild elevations of alanine aminotransferase levels (5 HGV-positive and 1 HGV-negative). An additional 14 HGV-infected children (aged 6 months to 14 years) with posttransfusion HGV infection were tested for anti-E2 3 months and 12 months after blood transfusion. None of the HGV RNA–positive serum samples were positive for anti-E2; however, 4 of the 8 children with resolving HGV infection were positive for anti-E2 1 year later.

Conclusions: Mother-to-infant transmission of HGV resulted in a high viral persistence rate and lack of immune responses to HGV. In contrast, anti-E2 appeared in children who recovered from posttransfusion HGV infection. Mode of transmission and age at infection may be important factors in determining persistent HGV infection and defective immune response to HGV. (J Pediatr 1998;133:382-5)