New research shows continued decline in vaccination rates among children
Microdata
Statistics Netherlands demographer and sociologist Ruben van Gaalen is Pijpers’ second supervisor: ‘This is the first study in the Netherlands to link childhood vaccination data with socio-demographic characteristics at such a detailed level. This is highly valuable knowledge for both policy-makers and researchers.’
Pijpers’ study uses ‘microdata’ from Statistics Netherlands (CBS). Microdata is data that can be linked at the level of the individual, company or address. This is used by universities, scientific organisations, planning agencies and research institutions – albeit under very tight supervision – to conduct their own statistical research. ‘Privacy and preventing the disclosure of individuals or companies is a strict requirement for this,’ explains Van Gaalen.
Valuable insights
In order to arrive at these insights, individual vaccination data from Præventis on children born between 2008 and 2020 was used. In a purpose-built secure environment, all the personal characteristics were replaced by a unique code (a technique known as pseudonymisation) and then linked to the national registers containing information on socio-demographic characteristics. The data points examined were: the mother's level of educational attainment, her country of origin, the disposable income of the household, the mother's main source of income, the degree of urbanisation, family size, use of childcare and what type of education the child attended.
Van Gaalen: ‘In the past, we were only able to link vaccination rates at the municipal or neighbourhood level with the aggregated population characteristics of the relevant municipality or neighbourhood. But now we have the ability to link the data with the individual level, and that provides us with much more precise insights.’
Partnership between RIVM and Statistics Netherlands
RIVM and Statistics Netherlands have been working closely together for many years in various areas, including health statistics. By combining expertise and data, we can provide a much more complete picture of public health. Statistical data on mortality, the use of health care services and lifestyle can therefore be analysed in an integrated manner.Falling vaccination rate
Joyce Pijpers explains: ‘Our analysis shows that, after adjusting for socio-demographic factors, the MMR vaccination rate at the age of 2 years in the Netherlands has declined significantly among children born between 2008 and 2020, and that the differences between groups are growing. The decline is most pronounced among Dutch children with a Moroccan and Turkish background. Among children born in 2009, the vaccination rate in those groups was 4 percent higher than that of children of Dutch origin, but for children born in 2020, the rates were 25 percent lower among children with a Moroccan background and 12 percent lower among children with a Turkish background, compared with children of Dutch origin.’ The study also revealed that children who did not attend childcare and children from larger families (four or more children) were less likely to be vaccinated than children who did attend childcare or were in smaller families (both groups 12 percent lower for the 2020 birth cohort).
The vaccination rate is also lower among children whose mothers are self-employed and children from households in the lowest income quartile, compared to children whose mothers work for an employer and children from households in the highest income quartile (8 percent and 7 percent lower respectively, 2020 birth cohort). The figures and trends for the DWTP vaccination rate were almost identical.
A better understanding of the world
Pijpers: ‘Because vaccination rates among children are often lower than average in specific population groups, there is an increased risk of localised outbreaks of infectious diseases. It is therefore important to understand more about why parents choose not to have their children vaccinated, especially in the groups where vaccination rates are the lowest. Social science research can provide highly valuable insights, helping us to design targeted interventions and improve childhood vaccination rates.’
Van Gaalen: ‘For Statistics Netherlands, it is a priority to partner with organisations like RIVM in order to facilitate this type of complex and important analysis by providing the data that is required, but also to join forces in terms of creating new statistics and valuable content.’