1 Spike-antibody responses to ChAdOx1 and BNT162b2 vaccines by demographic and clinical factors (Virus Watch study) Authors Madhumita Shrotri, Ellen Fragaszy, Cyril Geismar, Vincent Nguyen, Sarah Beale, Isobel Braithwaite, Thomas E Byrne, Wing Lam Erica Fong, Jana Kovar, Annalan M D Navaratnam, Parth Patel, Anna Aryee, Jamie Lopez Bernal, Anne M Johnson, Alison Rodger, Andrew C Hayward, Robert W Aldridge* on behalf of the Virus Watch Collaborative** Affiliations Institute of Health Informatics, University College London, UK (MS, EF, CG, VN, SB, IB, TB, WF, AN, PP, AA, RWA); Public Health England (MS, JLB); Institute of Epidemiology and Health Care, University College London, London, UK (JK, SB, ACH); Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK (EF); Institute for Global Health, University College London, London, UK (AMJ, AR). *Correspondence to: Prof Robert W Aldridge, r.aldridge@ucl.ac.uk **Virus Watch Collaborative: Susan Michie, Pia Hardelid, Linda Wijlaars, Eleni Nastouli, Moira Spyer, Ben Killingley, Ingemar Cox, Vasileios Lampos, Rachel A McKendry, Tao Cheng, Yunzhe Liu, Jo Gibbs, Richard Gilson Centre for Behaviour Change, University College London, London, UK (SM); Department of Population, Policy and Practice, UCL Great Ormond Street Institute of Child Health, London, UK (PH, LW, EN, MS, BK); Francis Crick Institute, London, UK (EN, MS); Health Protection and Influenza Research Group, Division of Epidemiology and Public Health, University of Nottingham School of Medicine, Nottingham, UK (BK); University College London Hospital, London, UK (BK); Department of Computer Science, University College London, London, UK (IC, VL); London Centre for Nanotechnology and Division of Medicine, London, University College London (RM); SpaceTimeLab, Department of Civil, Environmental and Geomatic Engineering, University College London, London, UK (TC, YL); Institute for Global Health, University College London, London, UK (JG, RG). . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted May 20, 2021. ; https://doi.org/10.1101/2021.05.12.21257102 doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.