Dynamics of SARS-CoV-2-specific antibodies during and after COVID19: Lessons from a biobank in Argentina

BackgroundBiobanks are instrumental for accelerating research. Early in SARS-CoV-2 pandemic, the Argentinean Biobank of Infectious Diseases (BBEI) initiated the COVID19 collection and started its characterization. MethodsBlood samples from subjects with confirmed SARS-CoV-2 infection either admitted to health institutions or outpatients, were enrolled. Highly exposed seronegative individuals, were also enrolled. Longitudinal samples were obtained in a subset of donors, including persons who donated plasma for therapeutic purposes (plasma donors). SARS-CoV-2-specific IgM and IgG levels, IgG titers and IgG viral neutralization capacity were determined. FindingsOut of 825 donors, 57.1% were females and median age was 41 years (IQR 32-53 years). Donors were segregated as acute or convalescent donors, and mild versus moderate/severe disease donors. Seventy-eight percent showed seroconversion to SARS-CoV-2 specific antibodies. Specific IgM and IgG showed comparable positivity rates in acute donors. IgM detectability rate declined in convalescent donors while IgG detectability remained elevated in early (74,8%) and late (83%) convalescent donors. Among donors with follow-up samples, IgG levels seemed to decline more rapidly in plasma donors. IgG levels were higher with age, disease severity, number of symptoms, and was more durable in moderate/severe disease donors. Levels and titers of anti-spike/RBD IgG strongly correlated with neutralization activity against WT virus. InterpretationThe BBEI-COVID19 collection served a dual role in this SARS-CoV-2 global crisis. First, it feed researchers and developers transferring samples and data to fuel research projects. Second, it generated highly needed local data to understand and frame the regional dynamics of the infection. FundingThis work was supported by a grant from the Agencia Nacional de Promocion de la Investigacion, el Desarrollo Tecnologico y la Innovacion (Agencia I+D+i) from Argentina through an extraordinary funding opportunity to improve the national response to COVID19 (Proyecto COVID N{degrees} 11, IP 285).