Determinants of COVID-19 vaccine uptake in the Netherlands: an ecological analysis

Background While overall COVID-19 vaccine uptake is high in the Netherlands, it lags behind in certain subpopulations. Aim We aimed to identify determinants associated with COVID-19 vaccine uptake at neighbourhood level to inform the strategy to improve uptake and guide research into barriers for vaccination. We focused on those aged 50 years and older, since they are at highest risk of severe disease. Methods We performed an ecological study using national vaccination register and socio-demographic data at neighbourhood level. Using univariate and multivariable generalized additive models we examined the (potentially non-linear) effect of each determinant on uptake. Results In those over 50 years of age, a higher proportion of individuals with a non-Western migration background and higher voting proportions for right-wing Christian and conservative political parties were at neighbourhood level univariately associated with lower COVID-19 vaccine uptake. In contrast, higher socioeconomic status and higher voting proportions for right-wing liberal, progressive liberal and Christian middle political parties were associated with higher uptake. Multivariable results differed from univariate results in that a higher voting proportion for progressive left-wing political parties was also associated with higher uptake. In addition, with regard to migration background only a Turkish background remained significant. Conclusion We identified determinants associated with COVID-19 vaccine uptake at neighbourhood level and observed heterogeneity between different subpopulations. Since the goal of the vaccination campaign is not only to reduce suffering and death by improving the average uptake, but also to reduce health inequity, it is important to focus on these hard-to-reach populations. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The study was funded by the Ministry of Health, Welfare and Sports. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Centre for Clinical Expertise at the RIVM assessed the above-mentioned research proposal. They verified whether the work complies with the specific conditions as stated in the law for medical research involving human subjects (WMO). They are of the opinion that the research does not fulfill one or both of these conditions and therefore conclude it is exempted for further approval by the ethical research committee. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available in aggregated and anonymized form upon reasonable request to the authors.