BMC Medicine (Jun 2021)

Persistence and baseline determinants of seropositivity and reinfection rates in health care workers up to 12.5 months after COVID-19

  • Carlota Dobaño,
  • Anna Ramírez-Morros,
  • Selena Alonso,
  • Josep Vidal-Alaball,
  • Gemma Ruiz-Olalla,
  • Marta Vidal,
  • Rocío Rubio,
  • Emma Cascant,
  • Daniel Parras,
  • Natalia Rodrigo Melero,
  • Pau Serra,
  • Carlo Carolis,
  • Pere Santamaria,
  • Anna Forcada,
  • Jacobo Mendioroz,
  • Ruth Aguilar,
  • Gemma Moncunill,
  • Anna Ruiz-Comellas

DOI
https://doi.org/10.1186/s12916-021-02032-2
Journal volume & issue
Vol. 19, no. 1
pp. 1 – 6

Abstract

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Abstract We 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.

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