1 Children develop strong and sustained cross-reactive immune responses against Spike protein following SARS-CoV-2 infection, with enhanced recognition of variants of concern Alexander C. Dowell 1 , Megan S. Butler 1† , Elizabeth Jinks 1† , Gokhan Tut 1† , Tara Lancaster 1 , Panagiota Sylla 1 , Jusnara Begum 1 , Hayden Pearce 1 , Eliska Spalkova 1 , Sandra Margielewska-Davies 1 , Graham S. Taylor 1 , Eleni Syrimi 1 , Frances Baawuah 2 , Joanne Beckmann 3 , Ifeanyichukwu Okike 2,4 , Shazaad Ahmad 5 , Joanna Garstang 6 , Andrew J Brent 7,8 , Bernadette Brent 7 , Georgina Ireland 2 , Felicity Aiano 2 , Zahin Amin-Chowdhury 2 , Samuel Jones 2 , Ray Borrow 9 , Ezra Linley 9 , John Poh 2 , Vanessa Saliba 2 , Gayatri Amirthalingam 2 , Kevin E Brown 2 , Mary E Ramsay 2 , Jianmin Zuo 1 , Paul Moss 1 *, Shamez Ladhani 2,10 * † *These author contributed equally 1. Institute of Immunology & Immunotherapy, Collage of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK 2. Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK 3. East London NHS Foundation Trust, 9 Allie Street, London E1 8DE, UK 4. University Hospitals of Derby and Burton NHS Foundation Trust, Uttoxeter New Road, Derby DE22 3NE, UK 5. Manchester University NHS Foundation Trust, Oxford Road, Manchester M13 9WL, UK 6. Birmingham Community Healthcare NHS Trust, Holt Street, Aston B7 4BN, UK 7. Oxford University Hospitals NHS Foundation Trust, Old Road, Oxford OX3 7HE 8. University of Oxford, Wellington Square, Oxford OX1 2JD, UK 9. Public Health England, Manchester Royal Infirmary, Manchester, United Kingdom 10. Paediatric Infectious Diseases Research Group, St. George’s University of London, London, UK All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 29, 2021. ; https://doi.org/10.1101/2021.04.12.21255275 doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.