Study Shows Non-Maternal Household Exposures Put Infants at Risk for Hepatitis B
- Infants living with non-maternal household members who have active hepatitis B face notable infection risks that are often missed by current screening approaches, according to research presented at...
- The retrospective cohort study examined 158,000 children under age 5 in 131,000 households who lived with Kaiser Permanente Northern California members on June 16, 2023.
- Non-maternal hepatitis B-positive contacts tended to be older than infected mothers, with a median age of 44 years compared with 38 years, and 76.5% were male, according to...
Infants living with non-maternal household members who have active hepatitis B face notable infection risks that are often missed by current screening approaches, according to research presented at IDWeek 2026 in Washington, DC, and covered by Contagion. While the U.S. Centers for Disease Control and Prevention updated its immunization guidance in January 2025 to recommend birth doses only for infants born to mothers with unknown or active hepatitis B status, a Kaiser Permanente study shows that 58.2% of young children exposed to the virus in their homes live with infected individuals other than their birth mothers.
Household Contacts Drive Most Infant Exposures
The retrospective cohort study examined 158,000 children under age 5 in 131,000 households who lived with Kaiser Permanente Northern California members on June 16, 2023. Researchers identified 2,024 children living in a household with a person who had active hepatitis B, creating an exposure pathway. Among those children, 846 were exposed by their birth mothers, while 1,178 were potentially exposed by another household member, as reported by Kaiser Permanente.
Non-maternal hepatitis B-positive contacts tended to be older than infected mothers, with a median age of 44 years compared with 38 years, and 76.5% were male, according to Contagion. Karen B. Jacobson, an infectious disease physician and research scientist at the Vaccine Study Center at the Kaiser Permanente Division of Research, explained that these contacts are most likely fathers, grandparents, or other relatives sharing the home. Jacobson noted that about four in 10 household contacts of a person with hepatitis B show serologic evidence of prior or current infection.
Vaccination Coverage Gaps Among Exposed Infants
All birth-exposed children in the study received the hepatitis B vaccine within seven days of birth, compared with 93.5% of household-exposed children and 86.7% of unexposed children, according to findings cited by Contagion. Investigators warned that infants who miss the birth dose remain vulnerable to infection during their first months of life before they enter daycare or school.
The hepatitis B virus is notably hardy and can survive on environmental surfaces for up to a week, meaning a single exposure through a wound or mucous membrane can transmit infection, according to Jacobson. About 640,000 adults in the United States live with chronic hepatitis B, and 90% of infants infected early in life develop chronic infections, according to Kaiser Permanente data.
Screening Limitations and Policy Criticisms
Jacobson cautioned against relying on clinicians to screen entire households, noting that medical providers are not in a position to assess the hepatitis B status of everyone living with an infant, nor can they account for close contacts outside the home such as childcare providers. Asking families about household status also has limits because half of people with chronic hepatitis B do not know they are infected.
Critics of the current federal guidance have warned that skipping the universal birth dose will cause preventable acute and chronic hepatitis B infections, liver cancers, and deaths, and add millions of dollars in healthcare costs, MedPage Today reported. A modeling study indicated that a proposed shared decision-making approach could increase chronic hepatitis B infections by 83%.
In contrast to previous CDC recommendations that all infants be vaccinated at birth, the guidance updated in January 2025 specifies vaccination should only be for infants whose mothers have unknown or active status. The newly proposed guidelines…really focus on the maternal exposure part of it, and not the horizontal exposure,
Jacobson said, describing the gap as an oversight in comments reported by Contagion. Amir Mohareb, an infectious-disease researcher at Harvard Medical School and Massachusetts General Hospital, said his team wanted to add evidence to ongoing conversations about what the potential impact of changing birth dose policies might be.