A Cornell University analysis warns that delaying the first hepatitis B vaccine dose in infancy could lead to more chronic infections, more serious liver disease and higher medical costs. The study, set to appear in the April 27, 2026 issue of JAMA Pediatrics, examined what happens when the long-standing birth dose is pushed back under the federal committee’s updated guidance.
The model looked at vaccination starts ranging from birth to 2 months, 7 months, 4 years and 12 years, and found that every delay came with worse outcomes. It linked postponement to more chronic HBV infections and more cases of cirrhosis and hepatic malignancies, while estimating healthcare costs from $16 million to more than $370 million depending on when children began the series and whether they completed the three-dose regimen.
That finding lands after the Advisory Committee on Immunization Practices revised its hepatitis B recommendation in late 2025. The updated guidance suggests waiting until later infancy to give the first dose when a child’s birth parent tests negative for the virus, a shift from the previous universal protocol that called for the first shot within 24 hours postpartum.
The Cornell team says the delay problem is not just about timing. Incomplete vaccine series adherence often follows a late start, and the models did not include herd immunity effects, which could make the real-world burden different. The study also notes that the risk of HBV pickup from household and community contacts rises as infection prevalence rises, a point that matters in a country where hepatitis B affects about 2.4 million people.
HBV is a major public health threat because it can progress to chronic infection, cirrhosis, liver failure and hepatocellular carcinoma. Newborns are especially vulnerable: up to 90% of infants infected at birth develop chronic hepatitis B infection, making mother-to-child transmission during delivery one of the most important targets for prevention. The study’s bottom line is plain. If the first dose is delayed, more children are likely to get sick, more will carry the virus for life, and the cost to the health system rises with each step away from the birth dose. The policy question now is whether the late-2025 change can hold up against those projected losses.
