Timeliness of infant vaccination and factors related with delay in Flanders, Belgium

Abstract

Achieving high vaccination coverage is a necessary, but not a sufficient indicator of the quality of avaccination programme, in terms of control and prevention of childhood infectious diseases. For optimalprotection of infants, timeliness of vaccination is increasingly recognized as another important target.The aim of this study was to assess the timeliness of measles-mumps-rubella (MMR) and diphtheria-tetanus-pertussis (DTP) vaccination in infants in Flanders (Belgium), and to identify predictors ofvaccination delay. The timeliness was assessed using the Kaplan–Meier estimator in three consecutivevaccination coverage surveys among children aged 18–24 months, conducted in 2005, 2008 and 2012,respectively. Factors associated with delayed administration of the vaccines were identified using Coxregression analysis.Over the time period, vaccination coverage for the first dose of MMR ranged from 94.0 to 96.6% and forthe third dose of DTP from 97.9 to 98.7%. However, up to 32% (for MMR1) and 95% (for DTP3) of infantsreceived vaccine doses delayed according to the recommended schedule. Although some improvementwas achieved over the last decade, further efforts are needed to reach risk groups with delays, morespecifically children vaccinated outside the baby well clinics, born from a mother originating from outsidethe European Union, children with a higher ranking or in families with a lower income.