Economic Impact of Delaying the Infant Hepatitis B Vaccination Schedule

Importance: Universal administration of hepatitis B (HepB) vaccine at birth is a cornerstone for hepatitis B virus (HBV) elimination efforts in the US. In 2025, the Advisory Committee on Immunization Practices (ACIP) recommended delaying HepB vaccine initiation among infants born to birth parents who tested negative for hepatitis B surface antigen (HBsAg). Objective: To evaluate the health and economic impact of delaying HepB vaccination among US infants. Design, Setting, and Participants: A Markov model of HBV infections was acquired among a cohort infants, born in 2025, up to age 18 years. The model incorporated HBsAg prevalence among birthing parents, HBsAg testing during pregnancy or delivery, vertical or perinatal and household or community HBV transmission among children, and sequalae from chronic infection. This study was conducted in the US. Exposures: Eight scenarios in which the first HepB dose was delayed at intervals between 2 months and 12 years, applied either only to infants born to birth parents who tested negative for HBsAg or to parents who either tested negative for HBsAg or had unknown HBsAg status. All delayed vaccination scenarios were compared with administering first HepB dose at birth. Scenarios were modeled with perfect and imperfect adherence to recommendations. Main Outcomes and Measures: Outcomes included acute and chronic HBV infections acquired until age 18 years, additional associated lifetime HBV-related morbidity and mortality, and health care costs (2025 US dollars). Results: The health and economic outcomes of 3 628 934 infants were modeled in this analysis. All delayed vaccination scenarios resulted in more infections, worse health outcomes, and higher costs than administering first HepB dose at birth. Under perfect adherence, delaying HepB vaccination by 2 months for infants of parents negative for HBsAg led to an additional 90 acute infections (range, 16-107), 76 chronic infections (range, 14-97), 29 HBV-related deaths (range, 6-53), with 16. 4 million in added costs for infants born during 1 year. Delaying to 12 years resulted in an additional 190 acute infections (range, 61-233), 50 deaths (range, 15-83), and nearly 30 million in added costs. Delaying HepB vaccination among infants of parents with unknown HBsAg status or imperfect adherence to the vaccination schedule amplified all negative outcomes. Conclusions and Relevance: Results of this economic evaluation quantified the potential impact of changing ACIP recommendations. Even brief delays in HepB vaccine initiation were associated with a substantial increase in HBV infections, adverse health outcomes, and health care costs.