Annals of Internal MedicineProjected Effect of 2026 Federal Changes to the Childhood Immunization Schedule on Chronic Hepatitis B Virus Infections in the United States

Researchers used a Markov model to compare universal birth-dose, deferred two-month, and shared decision-making hepatitis B vaccination strategies. The simulation followed 3.6 million US-born infants over 20 years. Compared with universal birth-dose vaccination, deferred and shared decision-making strategies projected more chronic infections and greater susceptibility entering adulthood. These are conditional estimates, not observed outcomes; assumed vaccine completion differed substantially between strategies.

Clinical Considerations

• Projected chronic infections were 255 with universal birth-dose vaccination, 303 with deferred vaccination, and 467 with shared decision-making vaccination.
• The corresponding increases were 19% and 83%; uncertainty intervals were wide and overlapped across strategies.
• Assumed vaccine completion was 91.1%, 87.1%, and 50.0%, respectively, making coverage a central driver of the comparison.
• At year 20, projected susceptible populations were 232,000, 474,000, and 1,806,000, respectively.
• A higher-transmission, lower-coverage scenario projected 1,700 infections with deferred vaccination and 2,192 with shared decision making.
• Uncertainty in horizontal transmission limits precision; the model does not isolate vaccination timing from differences in completion.

Practice Applications

• Interpret the 83% estimate alongside absolute infection counts, uncertainty intervals, and the assumed 50% completion rate.
• Distinguish modeled policy consequences from observed infections or independently verified changes to current recommendations.
• Review maternal screening, birth-dose delivery, and series-completion processes against applicable authoritative guidance.
• Discuss projections as conditional scenarios rather than predictions for an individual infant.