Source: Ngui SL, et al. Clin Infect Dis 1998;27:100-106.
Prompt administration of hepatitis B immune globulin and vaccine is effective in preventing maternal-infant transmission of HBV infection. Nevertheless, this report showed that 6.9% of infants at risk developed persistent HBV infection despite having received immunoprophylaxis and no mechanical obstetric intervention at birth.
Data from the Public Health Service for England and Wales showed that 1128 infants were born to hepatitis B surface antigen-positive mothers from 1988-1995. Of these, 568 of 786 infants born to e-antigenemic mothers were delivered vaginally; 552 (97.2%) received HBIg within 48 hours, 354 (62%) of whom received all three doses of vaccine. Sixteen (6.9%) of 232 infants available for testing at 1 year were surface-antigen positive, two of whom had vaccine-escape HBV mutants and two had mismatched DNA sequences.
Risk factors for the remaining 12 infants were compared to those for 22 seronegative controls from the same cohort. High levels of maternal circulating viremia (> 108 particles per mL of plasma), as well as four key allelic base changes in maternal HBV were significantly associated with transmission. There was also a trend suggesting that infants born to mothers infected with non-C (A, B, D, or E) genotypes were at higher risk for infection.
Although more effective interventions may be identified for high-risk infants such as these, this report suggests that infants born to antigenemic mothers should be screened for HBV infection irrespective of appropriate prophylaxis.
Despite participation in a nationalized health service, 214 of 568 (37.7%) infants at risk received inadequate immunoprophylaxis. It would be interesting to know how many of these infants were HBV seropositive at 1 year.