New CDC rules could leave babies at risk

On October 23, 2026, a study presented at IDWeek warned that new CDC hepatitis B vaccination guidelines could leave many babies vulnerable to the virus. The agency now recommends the jab only for infants whose mothers carry hepatitis B or have not been tested, moving away from the previous rule that all newborns receive the shot at birth.

The research, based on data from 158,000 children under five in 132,000 households in northern California, found that over 2,000 kids lived with a family member who had an active hepatitis B infection. Only 42 percent of the exposed children had a mother with the virus, while 58 percent were at risk from other relatives.

Because hepatitis B can spread through blood, tears, saliva and contaminated surfaces that can remain infectious for up to a week, exposure from family members is a significant risk. Despite this, 94 percent of children living with an infected relative had been vaccinated, compared to 87 percent of children with no household exposure.

Family members pose a larger risk

Dr. Karen Jacobson, the study’s lead author, said that vaccinating infants at birth protects against both known and unknown sources of transmission. She urged parents to ensure their children receive the hepatitis B shot within seven days of birth, especially when family members carry the virus.

The findings were shared at IDWeek, a joint meeting of major infectious disease societies, and are preliminary until published in a peer‑reviewed journal. The CDC’s updated guidance remains in place, but experts argue that broader birth‑time vaccination could reduce future liver disease risks.