Helen Branswell covers issues broadly related to infectious diseases, including outbreaks, preparedness, research, and vaccine development. Follow her on Mastodon and Bluesky. You can reach Helen on Signal at hbranswell.01.
Delaying the timing of vaccinating infants against hepatitis B -- an idea a federal vaccine advisory group will likely vote on later this week -- would neither improve the effectiveness of the vaccine nor make it safer to give to babies. But it would increase in the number of young children who become chronically infected with hepatitis B, an infection that carries a high risk a child will develop liver disease early in life, a report released Tuesday suggests.
A separate research effort, from modelers at several U.S. universities, attempted to quantify the impact of changing the policy. It suggested that delaying the start of vaccination by two months could lead to more than 1,400 babies becoming chronically infected with hepatitis B in the first year of the change, which could result in 304 cases of liver cancer and 482 hepatitis B-related deaths among those children as they aged. The modeling study is a preprint -- research that has not yet gone through peer review.
The report reviewing the scientific data on the hepatitis B "birth dose," from the University of Minnesota's Vaccine Integrity Program, examined the medical evidence surrounding the risks and benefits of administering a first dose of hepatitis B vaccine within 24 hours of birth, and what the available data suggests might happen if the birth dose is delayed. A vote on hepatitis B vaccination is on the draft agenda for this week's meeting of the Advisory Committee on Immunization Practices, a panel that advises the Centers for Disease Control and Prevention on immunization policy.
The draft agenda suggests Thursday, the first day of a two-day meeting, will be about the hepatitis B vaccine, followed by votes on the topic. It is believed the votes will be about the timing of vaccination against the virus. At a meeting in September, the group -- which is stacked with people who share health secretary Robert F. Kennedy Jr.'s anti-vaccine views -- deliberated whether to recommend delaying the birth dose of hepatitis B vaccine for babies born to mothers who test negative for the infection during pregnancy by at least one month. But the group decided to postpone the vote to a later meeting.
Inspired by the impending vote, the Vaccine Integrity Project -- which operates under the auspices of the University of Minnesota's Center for Infectious Disease Research and Policy -- decided to conduct a scientific literature review to address the questions about the hepatitis B birth dose policy that the ACIP discussion raised. A team of scientists reviewed roughly 400 studies published over a period of 40 years since the first hepatitis B vaccine was licensed.
They found only risks from changing the policy of recommending that all babies be given their first dose of hepatitis B vaccine within 24 hours of birth. Babies born to mothers who tested positive for the virus during pregnancy are recommended to receive hepatitis B immune globulin and their first dose of hepatitis B vaccine within 12 hours of birth. Likewise, vaccination within 12 hours of birth is recommended for babies born to mothers who have not been tested for the virus or whose test results are missing.
(The CDC recommends three doses of the hepatitis B vaccine in early childhood -- the first dose at birth, a second dose at 1 or 2 months of age, and the third between 6 and 18 months of age. This series confers at least 35 years of protection against hepatitis B, which is far more dangerous if contracted in early childhood than later in life.)
"The evidence overwhelmingly supports keeping the universal birth dose recommendation ... as is, and that there is no new evidence that we were able to identify that would suggest that changing the birth dose would make sense," Angela Ulrich, one of the authors of the report, told STAT in an interview.
"But we know that delaying the birth dose will increase the number of infections that could have been prevented," she said. "It would be a sad day to see us reverse a policy and put kids at risk of a lifelong disease and/or premature death."
There is no cure for hepatitis B infection. Most people who contract the virus clear it from their systems, though some will go on to be chronically infected -- a condition associated with higher risk of severe liver diseases and early death.
Only about 5% of adults who contract hepatitis B develop chronic infection. But when young children -- especially newborns and babies -- become infected, they have a 90% chance of developing chronic hepatitis B. Of those who do, about 25% will die prematurely from liver disease.
It is recommended that pregnant people be tested for hepatitis B during each pregnancy, to try to identify babies at risk of contracting the virus at birth. But tests aren't perfect, some pregnant people get no prenatal care, and there is a risk infection could occur after the test is conducted.
The report cited studies that show that between 12% and 18% of pregnant people do not receive hepatitis B testing, and only 35% of women who test positive receive all recommended follow-up care.
After the CDC recommended in 1991 that the first dose of hepatitis B vaccine be given at birth to all babies, regardless of the hepatitis B status of their mothers, the rate of hepatitis B infections in children in the U.S. plunged. In the early 1990s, around 1,600 babies and young children were infected annually; that number declined to fewer than 20 perinatal cases in recent years, the report said. In 2023, seven such cases were identified.
The United States is not the only country to give birth doses of the hepatitis B vaccine. The World Health Organization has recommended a birth dose of the vaccine since 2017; by 2024, 115 of 194 WHO member states had adopted a policy of giving a first dose of the vaccine at birth.
While the benefits of the policy have been clear to those who study this field, some vaccine-hesitant and vaccine-resistant parents have questioned why all babies should be vaccinated against a virus most commonly transmitted through sex or injection drug use. Some argue that babies born to mothers who tested negative for the virus during pregnancy should start their hepatitis B vaccination on a delay. (Though the birth dose is recommended, parents are not required to allow their newborns to be vaccinated. It's estimated that about 80% of babies in the U.S. get a birth dose of hepatitis B vaccine.)
Eric Hall, an assistant professor of epidemiology at Oregon Health and Science University, led an effort to estimate the impact of dropping the universal birth-dose policy. He and his co-authors were also moved to do the work in response to the ACIP's September meeting, when it became clear the panel was considering changing the policy.
Hall and colleagues modeled what might be expected if the hepatitis B vaccination initiation was delayed until 2 months, 7 months, 4 years, or 12 years of age, either for babies whose mothers tested negative during pregnancy, or for babies whose mothers tested negative or for whom test results were unknown. In the model, babies born to mothers who tested positive during pregnancy would continue to be treated with the current standard of care -- a dose of hepatitis B immune globulin and a first dose of hepatitis B vaccine within 12 hours of birth.
The model suggested that if the start of hepatitis B vaccination was delayed until 12 years of age, more than 2,700 preventable hepatitis B infections would occur in the first year after the policy went into effect. That could lead to 503 cases of liver cancer and 788 hepatitis B-related deaths among those children as they aged, with attendant excess medical costs of more than $300 million.
Hall told STAT that the projections are likely under-estimates, especially if a revised policy stayed in place for some years. Over time, the increase in hepatitis B infections among children would amplify. Children can contract the virus at day cares or in playgrounds, if they have contact with infected adults or other children. The highly infectious virus can remain stable on surfaces at room temperature for up to seven days, creating ample opportunities for the virus to spread. (It's estimated that 50% of people infected with hepatitis B are unaware of that fact.)
"If this recommendation were to stay in place for a longer period of time, not only would additional birth cohorts experience those infections, but the general community prevalence would go up and the risk of infection would go up," he said.
"The striking thing to me is this set of results indicates that even short delays in vaccination are substantially going to lead to more infections, more severe long-term health complications, and sharp increases in health care spending," said Hall.