A recent study warns that ending universal hepatitis B vaccination for newborns, as recommended by Health Secretary Robert F. Kennedy Jr. and his advisory panel, could result in a significant rise in chronic infections and increased risk of the disease among young Americans. Hepatitis B, a contagious virus that can cause severe liver disease, has been combated in the United States for decades by administering the first dose of the vaccine to all newborns within 24 hours of birth, or within 12 hours for infants born to infected mothers.

In December, an advisory group appointed by Kennedy recommended deferring the vaccine for infants born to mothers who test negative for hepatitis B until at least two months of age, leaving vaccination timing to parental choice. Kennedy and his team have argued that because the virus is primarily transmitted sexually, the immediate vaccine at birth is unnecessary unless the mother is infected. However, the virus can also spread through contact with infected individuals who may be unaware of their status, or through household items.

Following this, Kennedy proposed a new childhood vaccination schedule in January based on shared clinical decision-making, where vaccination would occur following consultation with a healthcare provider. Yet, a federal judge temporarily blocked these changes in March, reinstating the universal birth dose as recommended by the Centers for Disease Control and Prevention (CDC). The lawsuit opposing the new policy remains ongoing, leaving the possibility that vaccination could still shift to a later age.

The study, led by Dr. Amir Mohareb of Massachusetts General Hospital and Harvard Medical School, modeled the impact of these policy changes on the approximately 3.6 million infants born annually in the U.S. It found that delaying vaccination until two months of age could increase chronic hepatitis B infections by 19 percent, from around 255 to 303 cases per birth cohort by age 20. Adopting the shared decision-making approach was projected to raise chronic infections by 83 percent to 467 cases annually, with over half of children potentially entering adulthood susceptible to infection. These findings were published in the Annals of Internal Medicine.

Additional research published earlier this year supports these conclusions. One study estimated that postponing vaccination to two months would incur an additional $16.4 million in medical costs per annual birth cohort, while another reported that preventing infections under the delayed schedule would require screening significantly more pregnant women than is currently practiced.

Experts express concern that removing universal newborn vaccination could lead to increased transmission and chronic infection rates. Dr. Noele P. Nelson, an author involved in the economic impact study, emphasized that if the current trend continues, the U.S. could face a rise in chronic hepatitis B infections. Dr. José Romero, who formerly chaired the Advisory Committee on Immunization Practices (A.C.I.P.), noted that such a policy shift would normally require extensive committee evaluation due to its potential harm, and he expressed doubt that prior A.C.I.P. members would have supported these changes.

In June 2025, Kennedy dismissed the existing 17-member A.C.I.P. panel and appointed mostly vaccine-skeptical members who subsequently backed the deferred vaccination recommendations. Critics argue that the decision-making process lacked thorough consideration of epidemiological modeling.

Medical professionals caution that relying on shared clinical decision-making may weaken vaccine uptake. Dr. Nelson pointed out that, while informed consent is critical in any vaccination process, the weaker endorsement implied by shared decision-making could reduce adherence to immunization schedules. Additionally, patients may not always disclose behaviors that increase infection risk, and limited screening by healthcare providers could miss opportunities for early protection.

Given that hepatitis B transmission can occur through household contact, including use of objects like nail clippers contaminated with microscopic blood, experts underline the importance of early vaccination to prevent infection.

The U.S. Department of Health and Human Services has not commented on the latest study or the broader implications for hepatitis B vaccination policy. Meanwhile, the debate over the timing and universality of hepatitis B immunization continues to unfold amid ongoing legal and scientific scrutiny.