CIDRAP-Tens of thousands of US newborns could be exposed to hepatitis B at home, study suggests

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Tens of thousands of US newborns could be exposed to hepatitis B at home, study suggests

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Tens of thousands of US newborns could be exposed to hepatitis B at home, study suggests​

Liz Szabo, MA

Today at 8:00 a.m.
Hepatitis

Childhood Vaccines


Although many people are aware that newborns can be infected with hepatitis B from their mothers at birth, fewer realize that the infection also can be transmitted in the home.

Yet a new study finds that 1.3% of children under age 5 years were exposed to someone in their household with hepatitis B, a highly contagious disease that can cause liver failure and cancer.

Among the exposed children, more than half lived with someone with hepatitis B other than their mother, according to a study from Kaiser Permanente of Northern California. Children can be exposed to hepatitis B from their fathers, who are rarely tested for the virus, as well as grandparents, cousins, and others in the home.

Some of these children missed the birth dose of hepatitis B vaccine—given before newborns leave the hospital—and remained at risk of infection in the first few months of life, before attending daycare or school, according to the study, which is scheduled to be released today y at IDWeek, a major infectious disease conference in Washington, DC.

“It would be a tragedy if any infant is affected by a preventable infection,” Karen Jacobson, MD, MPH, first author of the study and a research scientist at the Vaccine Study Center at the Kaiser Permanente Northern California Division of Research, said at a press conference last week.

47,000 children a year could be exposed​

Although 1.3% of children may seem like a small percentage, that rate translates to 47,190 infants a year, considering that 3.63 million babies are born annually in the United States.

Researchers based their findings on medical records of people enrolled in Kaiser Permanente health insurance plans in northern California. The findings may not apply to other areas of the country or to people covered by other types of health insurance, Jacobson said.

It would be a tragedy if any infant is affected by a preventable infection.

It’s possible the study undercounted the true rate of exposure to hepatitis B, because children could have been exposed to household members who have never been tested. Children could also have been exposed to hepatitis by household members who use other types of health insurance.

The study authors do not know if any of the exposed children in the study developed hepatitis B, Jacobson said, because children are not routinely screened for the virus.

An argument for the universal birth dose​

The study “provides more proof of the continued need for universal hepatitis B vaccine birth dose in the US babies,” said Chari Cohen, DrPH, MPH, president of the Hepatitis B Foundation, a nonprofit educational and advocacy group.

“You do not want to risk missing any babies who can be exposed during infancy or childhood,” said Cohen, who was not involved in the new study. “We have a chance to protect 100% of babies and children from a life-long virus that causes liver cancer and greatly increases risk of premature death.”

Jacobson said she and her colleagues began the study last year after the Centers for Disease Control and Prevention (CDC) stopped recommending the hepatitis vaccine at birth for all newborns, instead recommending a “birth dose” only for babies whose mothers test positive for the virus or whose infection status is unknown. The decision downgraded the recommendation to shared decision making between parents and healthcare providers.

You do not want to risk missing any babies who can be exposed during infancy or childhood.

A federal judge has blocked the CDC’s recent vaccine recommendations, finding that the changes likely violated a law that dictates how government decisions are made. The fate of the immunization schedule changes will be decided in a legal case against the Department of Health and Human Services (HHS) and HHS Secretary Robert F. Kennedy Jr. by the American Academy of Pediatrics (AAP) and other medical groups.

The AAP continues to recommend that all infants receive their first dose of hepatitis B vaccine on their first day of life.

Many kids exposed at home were not tested​

Study participants included more than 158,000 children under age 5 years old on June 16, 2023, who were linked through their electronic medical records with their mother, and shared a street address with at least one other Kaiser Permanente Northern California member on that date. The researchers analyzed lab results and vaccination records through March 26, 2026.

More than 2,000 (1.3%) of 158,000 children lived in a household with a person with an active hepatitis B infection, according to the study.

Of those children, 42% were exposed to hepatitis B from their moms at birth and 58% were exposed to the virus later by someone in their household.

All children in the study exposed at birth were vaccinated against hepatitis B within seven days, compared with 93.5% of kids exposed by household members, and 87% of unexposed children.

“Hepatitis B vaccination coverage was very high overall, with 97% eventually receiving at least one hepatitis B vaccination dose,” Jacobson said. “However, 4.2% of the household-exposed children remained unvaccinated at 30 days of age, and some were never vaccinated before our study ended.”

While 95% of babies exposed to hepatitis B at birth were tested for the virus, only 3.6% of household-exposed children were ever tested, along with 0.4% of unexposed children, Jacobson said.

“Even if it is possible to accurately identify every single maternal infection, this would not account for potential exposure to an infected father, grandparent, or another person living in the household, and of course anyone that they might come into close contact with outside the household,” Jacobson said.