Missed hepatitis B birth dose vaccine is a risk factor for incomplete vaccination at 18 and 24 months

•Delays in childhood vaccinations may be able to be traced back to birth.•In this study,fewer than 50% of babies who missed the birth dose of hepatitis B vaccine were fully vaccinated at age 2.•It is important to develop patterns of timely vaccination to prevent serious downstream consequences.•Medical providers should start talking with parents about childhood vaccinations long before a woman becomes pregnant. To determine whether missing the HepB birth dose vaccine is a risk factor for incomplete vaccination later in childhood. This was a retrospective cohort study of infants born over one year at an academic medical center. The “not vaccinated at birth” group consisted of all infants who did not receive the HepB birth dose vaccine by seven days of life, while the “vaccinated at birth” group included infants who did receive the birth dose. The primary outcome was vaccination status at 18 months of age, determined from the state vaccination registry. Infants “not vaccinated at birth” had lower vaccination rates. At 18 months, 44% of the “vaccinated at birth” group received all recommended vaccines, compared with 23% of the “not vaccinated at birth” group (p