Introduction The Advisory Committee on Immunization Practices (ACIP) recommends administering the first dose of hepatitis B vaccine at birth, making it the first vaccine that many children receive. However, few studies examine whether children who miss the birth dose are at increased risk of vaccination delay. This study investigates birth dose as a determinant of up-to-date immunization status at 18 months, considering seven core childhood vaccine series: DTaP, polio, MMR, Hib, Hep B, varicella, and PCV13.
Methods Cross-sectional data were collected in 2017 by National Immunization Survey - Child (NIS-Child), a nationally representative survey of 19-to-35-month-olds living the United States, and were analyzed in 2019. The primary outcome was combined 7-vaccine series (4:3:1:3:3:1:4) up-to-date status at 18 months. Doubly robust estimates of association were calculated using survey logistic regression and propensity scores estimated with boosted classification and regression trees (CART).
Results Children who received the birth dose had 2.01 (95% CI 1.74, 2.33) times the odds of being up-to-date on the combined 7-vaccine series as children who did not. Odds ratios for all seven individual vaccine series were positive, ranging from 1.59 (1.28, 1.97) for MMR to 4.97 (3.97, 6.24) for hepatitis B.