Dobaño, CarlotaRamírez-Morros, AnnaAlonso, SelenaVidal Alaball, JosepRuiz-Olalla, GemmaVidal, MartaRubio, RocíoCascant, EmmaParras, DanielRodrigo Melero, NataliaSerra, PauCarolis, CarloSantamaria, PereForcada, AnnaMendioroz, JacoboAguilar, RuthMoncunill, GemmaRuiz-Comellas, Anna2021-11-172021-11-172021Dobaño C, Ramírez-Morros A, Alonso S, Vidal-Alaball J, Ruiz-Olalla G, Vidal M, Rubio R, Cascant E, Parras D, Rodrigo Melero N, Serra P, Carolis C, Santamaria P, Forcada A, Mendioroz J, Aguilar R, Moncunill G, Ruiz-Comellas A. Persistence and baseline determinants of seropositivity and reinfection rates in health care workers up to 12.5 months after COVID-19. BMC Med. 2021;19(1):155. DOI: 10.1186/s12916-021-02032-21741-7015http://hdl.handle.net/10230/49000We assessed the duration and baseline determinants of antibody responses to SARS-CoV-2 spike antigens and the occurrence of reinfections in a prospective cohort of 173 Spanish primary health care worker patients followed initially for 9 months and subsequently up to 12.5 months after COVID-19 symptoms onset. Seropositivity to SARS-CoV-2 spike and receptor-binding domain antigens up to 149-270 days was 92.49% (90.17% IgG, 76.3% IgA, 60.69% IgM). In a subset of 64 health care workers who had not yet been vaccinated by April 2021, seropositivity was 96.88% (95.31% IgG, 82.81% IgA) up to 322-379 days post symptoms onset. Four suspected reinfections were detected by passive case detection, two among seronegative individuals (5 and 7 months after the first episode), and one low antibody responder. Antibody levels significantly correlated with fever, hospitalization, anosmia/hypogeusia, allergies, smoking, and occupation. Stable sustainment of IgG responses raises hope for long-lasting COVID-19 vaccine immunity.application/pdfeng© The Author(s). 2021 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.info:eu-repo/semantics/articlehttp://dx.doi.org/10.1186/s12916-021-02032-2AntibodiesBaseline determinantsCOVID-19CohortDurationHealth care workersKineticsReinfectionSARS-CoV-2Spike antigeninfo:eu-repo/semantics/openAccess