Dutch national immunization schedule: compliance and associated characteristics for the primary series.

In the Netherlands, the recommended priming immunization schedule for diphtheria, tetanus, pertussis and polio (DTaP-IPV) is at 2, 3 and 4 months of age. We evaluated the compliance with the recommended schedule, as well as its characteristics. We included all infants born between 2007 and 2012 who received minimally one DTaP-IPV vaccination (n = 1,061,578). Infants complied with the schedule if they received the first vaccination between 6 and 9 weeks of age, and the second and third vaccination 2-6 weeks after the first and second vaccination. We examined associations between compliance and several characteristics using log-binomial regression. Compliance for the first, second and third vaccination was 81.6, 88.3 and 84.2%, respectively. Compliance with the total recommended schedule was 64.5%, and increased from 60.1% for 2007 to 68.5% for 2012. Compliance was higher for full-term infants (65.9%), infants with normal birth weight (66.0%) and when both parents were born in the Netherlands (66.8%).

CONCLUSION: Delayed vaccination during the primary vaccination schedule occurs in one sixth of the Dutch children. Efforts to improve compliance should be focused in particular on preterm infants, infants with low birth weight and infants whose parents are not born in the Netherlands. What is Known: • A delayed start of vaccination leads to a longer period at risk for infectious diseases, e.g. pertussis • Delayed vaccination is associated with several factors including prematurity, low birth weight, family size, birth order, low socioeconomic status and health status of the child What is New: • Compliance with the recommended priming immunization schedule for diphtheria, tetanus, pertussis and polio was 64.5%, and increased from 60.1% for 2007 to 68.5% for 2012 • If the first vaccination was delayed, there was a higher chance that the following vaccinations were administered 'out-of-schedule' as well, resulting in even a higher age at second and third vaccination.