Unexposed populations and potential COVID-19 burden in European countries as of 21st November 2021

We estimate the potential remaining COVID-19 burden in 19 European countries by estimating the proportion of each country’s population that has acquired immunity to severe disease through infection or vaccination. Our results suggest that many European countries could still face a substantial burden of hospitalisations and deaths, particularly those with lower vaccination coverage, less historical transmission, and/or older populations. Continued non-pharmaceutical interventions and efforts to achieve high vaccination coverage are required in these countries to limit severe COVID-19 outcomes. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was funded by the National Insitute for Heatlh Research (NIHR) (NIHR200908) and the Wellcome Trust (206250/Z/17/Z) (LACC, TWR, AJK). The work was partly supported by funding from the European Union's Horizon 2020 research and innovation programme - project EpiPose (101003688: RCB); the FCDO/Wellcome Trust (Epidemic Preparedness Coronavirus research programme 221303/Z/20/Z: KvZ); the Wellcome Trust (210758/Z/18/Z: SA); NIHR (NIHR200929) (NGD); UK MRC (MC\_PC\_19065) (NGD) and UKRI Research England (NGD). The funders had no role in the 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: This study involves only openly available human data, which can be obtained from: [https://github.com/robert-koch-institut/COVID-19-Impfungen\_in\_Deutschland/][1] I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the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 and code used in this manuscript are available online at [https://github.com/LloydChapman/covid\_remaining\_burden][2] and or at the links below. [https://github.com/LloydChapman/covid\_remaining\_burden][2] [1]: https://github.com/robert-koch-institut/COVID-19-Impfungen_in_Deutschland/ [2]: https://github.com/LloydChapman/covid_remaining_burden