Most young children exposed to household hepatitis B were infected outside maternal transmission risk

A study presented at IDWeek found that 58.2% of young children living with someone with active hepatitis B were exposed through a household contact other than their birth mother, highlighting gaps in maternal-only screening and early vaccination.

A study presented at IDWeek in Washington suggests that hepatitis B exposure in early childhood is not confined to mothers with known infections. Researchers found that more than half of young children living with someone who had an active hepatitis B infection were exposed through another household member, not their birth mother, underscoring the limits of screening only expectant mothers.

The retrospective cohort study drew on Kaiser Permanente Northern California data and included children younger than five years old linked to their birth mothers and living with at least one household contact using the health system. Among 158,169 children in 131,800 households, 2,024, or 1.3%, lived in a home with an active hepatitis B exposure. Of those children, 41.8% were exposed at birth by their mothers, while 58.2% were exposed by another household contact. The findings echo guidance from the CDC, the Department of Health and Human Services and the American Academy of Pediatrics, all of which recommend universal hepatitis B vaccination for infants, with the first dose given soon after birth.

Karen B. Jacobson, an infectious disease physician and research scientist at the Kaiser Permanente Northern California Division of Research, said the results show why relying solely on maternal screening leaves gaps. In her presentation, she said household exposure could come from a father, grandparent or another person living in the home, and that some exposed infants never received a birth dose of the vaccine. The study also found that while all infants exposed at birth were vaccinated within a week, 4.2% of children exposed through the household went more than a month without vaccination, and two were never vaccinated.

Testing patterns were also uneven. Nearly all children exposed at birth were tested for hepatitis B, but only 3.6% of those exposed through another household member were ever tested. Jacobson said that suggests a gap in care for families where an infected contact is known, while also cautioning that the true risk may be higher because the analysis could not capture undiagnosed infections, non-Kaiser Permanente household members or other close contacts outside the home. Paul Offit, a paediatric infectious disease specialist at Children’s Hospital of Philadelphia who was not involved in the study, said the findings reinforce the importance of vaccinating newborns early because infants can acquire the virus from sources other than their mothers, and infection in early life carries a high risk of chronic disease later on.