Bibliographical noteFunding Information:
This study was supported by the UCLH/UCL NIHR Biomedical Research Centre and funding from the MRC UKRI (grant ref: MC_PC_19082). This work was supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001169, FC001078), the MRC (FC001169, FC001078) and the Wellcome Trust (FC001169, FC001078). CS is funded by a Royal Society Napier Professorship, the Rosetrees Trust, and the Breast Cancer Research Foundation; receives grant support from Pfizer, AstraZeneca, BMS, Roche-Ventana, Boehringer Ingelheim, and Ono Pharmaceutical; has consulted for Pfizer, Novartis, GlaxoSmithKline, MSD, BMS, Celgene, AstraZeneca, Illumina, Genentech, Roche-Ventana, GRAIL, Medicxi, and the Sarah Cannon Research Institute; is a shareholder of Apogen Biotechnologies, Epic Bioscience, and GRAIL; and has stock options in and is co-founder of Achilles Therapeutics. SGan is an MRC Senior Clinical Fellow. All other authors declare no competing interests. We thank all the dedicated HCWs who have worked tirelessly on the frontline and made the effort to contribute their samples and questionnaires to this study. We also thank staff at the Joint Research Office, Pushpsen Joshi, and the UCL/UCLH NIHR Biomedical Research Centre, Nick McNally, and Bryan Williams for their support.