Replacing universal hepatitis B virus (HBV) vaccination at birth with shared clinical decision-making and delaying universal vaccination until 2 months could increase chronic hepatitis B virus infections acquired during childhood.
Investigators developed a Markov cohort state transition model using published estimates of maternal HBV prevalence, prenatal screening, childhood vaccination coverage, and age-specific infection risks. The analysis simulated 3 vaccination strategies in a hypothetical cohort of 3.6 million US-born infants followed through age 20 years. These included universal birth-dose vaccination, deferred vaccination beginning at age 2 months, and vaccination through shared clinical decision-making. The strategies reflected recommendations prior to December 2025 and federal policy changes introduced in December 2025 and January 2026.
Outcomes included the projected number of chronic HBV infections acquired during the first 20 years of life, resolved HBV infections, and the number of children remaining susceptible to infection at age 20 years. The investigators conducted scenario and sensitivity analyses to evaluate the effects of changes in vaccine uptake, maternal HBV prevalence, and childhood exposure risks.
In the base-case analysis, universal birth-dose vaccination was projected to result in 255 chronic HBV infections. Deferring vaccination until age 2 months increased the projected number to 303 infections, representing a 19% relative increase. Under shared decision-making, the model projected 467 infections, corresponding to an 83% relative increase.
Differences in HBV susceptibility at age 20 years were more pronounced. About 232,000 children were projected to remain susceptible following universal birth-dose vaccination vs. 474,000 under deferred vaccination and 1.8 million under shared decision-making. Under the latter strategy, about 50% of the modeled birth cohort would enter adulthood susceptible to HBV infection.
The model assumed vaccine-series completion rates of 91% with universal birth-dose vaccination, 87% with deferred vaccination, and 50% with shared decision-making. When vaccine uptake was further reduced to 75% under deferred vaccination and 26% under shared decision-making, projected chronic infections increased to 357 and 575, respectively. The number of children remaining susceptible at age 20 years increased to about 912,000 and 2.7 million, respectively.
In a higher-risk scenario incorporating reduced birth-dose vaccination among infants born to mothers with positive or unknown hepatitis B surface antigen status, higher maternal HBV prevalence, and increased childhood exposure, projected chronic infections increased to 1,700 under deferred vaccination and 2,192 under shared decision-making. These estimates were more than 6 times the 255 infections projected under the base-case universal birth-dose strategy.
Further analyses indicated that later initiation of vaccination could increase infections. Beginning the vaccine series at age 12 years resulted in 632 projected chronic infections under the deferred universal strategy and 685 under shared decision-making. Across 1,000 probabilistic sensitivity simulations, universal birth-dose vaccination consistently resulted in fewer chronic HBV infections than either alternative.
Limitations included uncertainty surrounding household and community HBV transmission risks. The model did not explicitly account for partial immunity among children who received an incomplete vaccine series or differences in transmission risks across household and community settings. It also did not simulate subsequent liver disease, mortality, onward transmission, or economic consequences. Additionally, continued universal birth-dose recommendations from some state health departments and professional medical societies could limit the applicability of projections assuming broader implementation of the federal changes.
"Even a small number of additional infections in childhood could have large clinical, public health, and economic effects," wrote lead study researcher Amir M. Mohareb, MD, of Massachusetts General Hospital and Harvard Medical School, and colleagues.
Full disclosures are available in the published article.
Source: Annals of Internal Medicine
