Microdata
Demographer and sociologist at CBS Ruben van Gaalen is Pijpers second supervisor: This is the first study in the Netherlands where vaccination data of children have been linked at such a detailed level to sociodemographic characteristics. This provides valuable insights for policy and further research.For this study, microdata from CBS were used.
Microdata are linkable data at the individual, company, and address level that Dutch universities, scientific organizations, planning agencies, and research institutes in several other EU countries can use under strict conditions to conduct statistical research themselves. Van Gaalen: Ensuring privacy and preventing disclosure of individuals or companies is a requirement.
Characteristics
To gain insights, individual vaccination data from Præventis of children born between 2008 and 2020 were used. In a specially secured environment, personal characteristics were replaced by a unique code (pseudonymized) and then linked to national registers with information on sociodemographic characteristics. Characteristics studied include: mothers education level, country of origin, household disposable income, mothers main income source, urbanization, family size, participation in childcare, and the distinction between public education and various categories of special education.Van Gaalen: In the past, vaccination rates at municipal or neighborhood level were roughly related to aggregated population characteristics of municipalities or neighborhoods. Linking at the individual level provides precise insights.
RIVM and CBS
The RIVM and CBS have long worked closely together in various fields, including health statistics. By combining expertise and data, a more complete picture of the populations health emerges. Statistical data on mortality, healthcare use, and lifestyle can thus be analyzed in context.Declining Vaccination Rate
Joyce Pijpers: The analyses show that, after correcting for sociodemographic factors, the MMR vaccination rate at age 2 in the Netherlands has significantly declined among children born between 2008 and 2020, with increasing differences between groups. The decrease is strongest among Dutch children of Moroccan and Turkish origin. For children born in 2009, their vaccination rate was still 4 percent higher than that of children of Dutch origin, but for children born in 2020, it was 25 percent and 12 percent lower, respectively, than children of Dutch origin. It also appeared that children who did not attend childcare and children from larger families (four or more children) were vaccinated less often than children who did attend childcare or lived in smaller families (both groups −12 percent in birth year 2020).The vaccination rate was lower among children of mothers who are self-employed and among children from households with the 25 percent lowest incomes, compared to children of mothers with salaried jobs and children from households with the 25 percent highest incomes (respectively −8 percent and −7 percent in birth year 2020). Trends for the DTP vaccination rate were almost identical.
Better Understanding
Pijpers: Because unvaccinated children often cluster within certain groups, the risk of local outbreaks increases. It is therefore important to better understand why parents do not vaccinate their children, especially in groups where vaccination rates are lowest. Social scientific research can provide valuable insights to develop targeted interventions and improve vaccination rates.Van Gaalen: CBS is happy to collaborate with institutions like the RIVM to make such complex and important analyses possible from a data perspective, but also to combine forces statistically and substantively.
