SP declares conducting contract research (testing of vaccinee sera for neutralising activity against SARS-CoV-2) for Valneva, unrelated to this work, and serving as an advisor for BioNTech, unrelated to this work. GMNB declares serving as a lecturer for Pfizer, unrelated to this work. AD-J declares serving as an advisor for Pfizer, unrelated to this work. TW declares serving as an advisor for Pfizer, unrelated to this work. All other authors declare no competing interests. GMNB and AD-J acknowledge funding from Niedersächsisches Ministerium für Wissenschaft und Kultur (the Ministry of Science and Culture of Lower Saxony; 14-76103-184) and the COVID-19-Research Network Lower Saxony (COFONI) (project 4LZF23). GMNB acknowledges funding by the European Regional Development Fund (ZW7-85151373). AD-J acknowledges funding by the European Social Fund (ZAM5-87006761). TW acknowledges funding by the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation) under Germany's Excellence Strategy EXC 2155 RESIST (project 390874280). SP acknowledges funding by the EU project UNDINE (grant agreement number 101057100), COFONI through funding from the Ministry of Science and Culture of Lower Saxony (14-76103-184—projects 7FF22, 6FF22, and 10FF22) and DFG (PO 716/11-1). The funders had no role in the design and execution of the study, the writing of the manuscript, and the decision to submit the manuscript for publication. The authors did not receive payment by a pharmaceutical company or other agency to write the publication. All authors had access to the data and accept responsibility to submit for publication. CH and MH are joint first authors. GMNB and AD-J are joint senior authors.