5 minSociety
Study Warns Hepatitis B Cases Could Rise 225% Under New Vaccine Guidance
A new modeling study in Annals of Internal Medicine projects that shifting hepatitis B vaccination away from the birth dose could sharply increase chronic infections among U.S. children, as pediatricians and states challenge the revised federal guidance.
A modeling study published in Annals of Internal Medicine projects that chronic hepatitis B infections among U.S. children could rise by 225% under revised federal vaccine guidance that moves the first dose away from birth for infants whose mothers test negative for the virus. The research arrives as pediatricians and more than a dozen states challenge the change in court, and it adds quantitative weight to a debate that has so far been driven largely by professional opinion.
Hepatitis B is a liver virus that can pass from mother to child during birth and spread through contact with infected blood or semen. Among babies infected before their first birthday, up to 90% develop a chronic, potentially lifelong infection. There are treatments but no cure, and many people do not learn they carry the virus until their liver fails or cancer develops years later. Untreated infections acquired early in life carry a one in four lifetime chance of liver cancer.
The United States began routinely recommending hepatitis B vaccination for all infants in 1991, and later guidance specified that the first dose should be given within 24 hours of birth. In December 2025, the Centers for Disease Control and Prevention under the Trump administration stopped recommending that practice for babies born to mothers who test negative. The agency instead advised a shared decision-making model in which parents and clinicians decide together whether to vaccinate shortly after birth or wait until no earlier than 2 months of age. For babies whose mothers test positive or whose status is unknown, the CDC continues to recommend a dose shortly after birth.
The new study used computer modeling to simulate the infection status of an entire year of U.S. births — about 3.6 million children — over their first 20 years of life under several scenarios. Researchers compared continued adherence to the former CDC recommendations, a delayed first dose, and a shared decision-making approach. If only about 26% of children are vaccinated at 2 months — an estimate of what shared decision-making would produce — chronic hepatitis B cases would rise by 225%. If the first dose is delayed until 2 months and 75% of infants receive it, chronic cases would still increase by 19% compared with universal birth-dose vaccination.
«It's been challenged in many states and by professional societies, but we wanted to add some evidence to the conversation about what the potential impact of those changes could be,» said Dr. Amir Mohareb, an infectious-disease researcher at Harvard Medical School and Massachusetts General Hospital and an author of the study. He noted that the model covers a single year of births. «Imagine that happening year after year after year after year. That could quickly become thousands and thousands of new infections, and even a small number of new infections could result in lifelong chronic infection that could be detrimental to families, lead to more cases of cancer, and become costly to the health care system.»
The American Academy of Pediatrics continues to recommend vaccination at birth for all infants, and 15 states have sued the Trump administration over changes to the vaccination schedule. Two other recent modeling studies have examined the revised guidance. One found that ending birth-dose vaccination would require a substantial increase in screening pregnant women to keep infant infections down. Another, focused on costs, found that delaying the first dose by two months would add $16.4 million in health care spending on new infections even if every child eventually received the vaccine.
Mohareb said the three studies complement one another and provide evidence without the need for a clinical trial. Decades ago, he said, trials already established the efficacy of the existing approach, «so that we would have the benefit now of advancing medical progress and not needing to reopen that question.»
8
