Mental illness and COVID-19 vaccination: a multinational investigation of observational & register-based data

Background Individuals with mental illness are at higher risk of severe COVID-19 outcomes. However, previous studies on the uptake of COVID-19 vaccination in this population have reported conflicting results. Therefore, we aimed to investigate the association between mental illness and COVID-19 vaccination uptake, using data from five countries. Methods Data from seven cohort studies (N=325,298), and the Swedish registers (8,080,234), were used to identify mental illness and COVID-19 vaccination uptake. Multivariable modified Poisson regression models were conducted to calculate the prevalence ratio (PR) and 95% CIs of vaccination uptake among individuals with v.s. without mental illness. Results from the cohort studies were pooled using random effects meta-analyses. Findings Most of the meta-analyses performed using the COVIDMENT study population showed no significant association between mental illness and vaccination uptake. In the Swedish register study population, we observed a very small reduction in the uptake of both the first (prevalence ratio [PR]: 0.98, 95% CI: 0.98-0.99, p<0.001) and second dose among individuals with mental illness; the reduction was however greater among those not using pyschiatric medication (PR: 0.91, 95% CI: 0.91-0.91, p<0.001). Conclusions The high uptake of COVID-19 vaccination observed among individuals with most types of mental illness highlights the comprehensiveness of the vaccination campaign, however lower levels of vaccination uptake among subgroups of individuals with unmedicated mental illness warrants attention in future vaccination campaigns. ### Competing Interest Statement EMF received speakers honoraria from Astra Zeneca. OAA is a consultant for Cortechs.ai, and received speakers honoraria from Janssen, Lundbeck, Sunovion, Otsuka. PFS is a shareholder and on the advisory committee of Neumora Therapeutics. FN owns some AstraZeneca shares. ### Funding Statement This work was supported by grants from NordForsk () [COVIDMENT, grant numbers 105668 and 138929] and Horizon 2020 () [CoMorMent, 847776]. Estonian Biobank is supported by the European Union through the European Regional Development Fund ([https://ec.europa.eu/regional\_policy/funding/erdf\_en][1]) [Project No. 2014-2020.4.01.15-0012]. KL and KK were supported by the Estonian Research Council () [grant PSG615] and Estonian sub-project of NordForsk project no. 105668. Generation Scotland received core support from the Chief Scientist Office of the Scottish Government Health Directorates () [CZD/16/6] and the Scottish Funding Council () [HR03006] and is currently supported by the Wellcome Trust () [216767/Z/19/Z]. Recruitment to the CovidLife study was facilitated by SHARE- the Scottish Health Research Register and Biobank (). SHARE is supported by NHS Research Scotland, the Universities of Scotland and the Chief Scientist Office of the Scottish Government. Omtanke2020 was supported by funding from the Swedish Research Council () [D0886501]. SCIFI-PEARL has funding to support this study from the SciLifeLab National COVID-19 Research Program, financed by the Knut and Alice Wallenberg Foundation () [grants KAW 2021-0010/VC2021.0018 and KAW 2020.0299/VC 2022.0008], and the Swedish Research Council () [grants 2021-05045 and 2021-05450]. SCIFI-PEARL also has basic funding based on grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF agreement () [grants ALFGBG-938453, ALFGBG-971130, ALFGBG-978954] and from FORMAS (Research Council for Environment, Agricultural Sciences and Spatial Planning), a Swedish Research Council for Sustainable Development () [grant 2020-02828]. OAA and BW were also supported by the Research Council of Norway () [#223273 and #324620, resepctively]. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. ### 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: Ethical approvals for cohorts: Estonian Committee on Bioethics and Human Research (1.1 12/1277 and 1.1 12/2860) National Bioethics Committee (Iceland) (NBC no 20 073, 21 071) as well as the National Data Protection Authority Regional Committee for Medical Research Ethics (Norway), reference number: 125510 Regional Committees for Medical and Health Research Ethics (Norway), (127708/14140/20138) East of Scotland Research Ethics Service (EoSRES) Swedish Ethical Review Authority (2020 01785) Ethical approval for register data (SCIFI-PEARL): Swedish Ethical Review Authority (2020-01800 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][2]. 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, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The raw data underlying this article were subject to ethical approval and cannot be shared publicly due to data protection laws in each participating country. [1]: https://ec.europa.eu/regional_policy/funding/erdf_en [2]: http://ClinicalTrials.gov