A novel measles outbreak control strategy in the Netherlands in 2013–2014 using a national electronic immunization register: A study of early MMR uptake and its determinants

Background: During a large measles outbreak in the Netherlands in 2013–2014, infants aged

6–14 months living in municipalities with low (<90%) measles-mumps-rubella (MMR) coverage were

individually invited for an early MMR using the national electronic immunization register, Præventis.

We estimated uptake of early MMR prior to and during the 2013–2014 outbreak and assessed determinants

for early MMR vaccination.

Methods: We obtained vaccination records from Præventis, and defined early MMR as vaccination before

415 days (13 months) of age. A multi-level multivariable logistic regression model, restricted to infants

with three diphtheria-pertussis-tetanus-polio (DPTP) vaccinations was used to examine the association

between early MMR uptake and sex, parents’ country of birth, socioeconomic status (SES; at postcode

level) and voting proportions for the Reformed Political Party (SGP; at municipal level), used as a proxy

for religious objections towards vaccination.

Results: In the 29 municipalities with low MMR coverage, uptake of early MMR was 0.5–2.2% prior to the

outbreak. Between July 2013 and March 2014, 5,800 (57%) invited infants received an early MMR. Among

infants with three DPTP, 70% received an early MMR. Only 1% of infants without prior DPTP received an

early MMR. Lower early MMR uptake was associated with a higher SGP voter-ship (OR 0.89 per 5%

increase, 95%CI 0.83–0.96), parents’ with unknown country of birth (OR 0.66 95%CI 0.47–0.93) and compared

with very high SES, high SES had significantly lower early MMR uptake (OR 0.66 95%CI 0.50–0.87).

Discussion: This is the first study describing use of Præventis during an outbreak and to assess determinants

of early MMR uptake. More than half of invited infants obtained an early MMR. SES, parents’ with

unknown country of birth and religious objections towards vaccination were found to be associated with

lower early MMR uptake. In future outbreaks, these determinants could be used to tailor intervention

strategies.