Infection induced SARS-CoV-2 seroprevalence and heterogeneity of antibody responses in a general population cohort study in Catalonia Spain
Marianna Karachaliou, Gemma Moncunill, Ana Espinosa, Gemma Castaño‐Vinyals, Alfons Jiménez, Marta Vidal, Rebeca Santano, Diana Barrios, Laura Puyol, Anna Carreras, Leonie Mayer, Rocío Rubio, Beatriz Cortés, Vanessa Pleguezuelos, Cristina O’Callaghan‐Gordo, Serena Fossati, Ioar Rivas, Delphine Casabonne, Martine Vrijheid, Luís Izquierdo, Ruth Aguilar, Xavier Basagaña, Judith García‐Aymerich, Rafael de Cid, Carlota Dobaño, Manolis Kogevinas
Abstract
Sparse data exist on the complex natural immunity to SARS-CoV-2 at the population level. We applied a well-validated multiplex serology test in 5000 participants of a general population study in Catalonia in blood samples collected from end June to mid November 2020. Based on responses to fifteen isotype-antigen combinations, we detected a seroprevalence of 18.1% in adults (n = 4740), and modeled extrapolation to the general population of Catalonia indicated a 15.3% seroprevalence. Antibodies persisted up to 9 months after infection. Immune profiling of infected individuals revealed that with increasing severity of infection (asymptomatic, 1-3 symptoms, ≥ 4 symptoms, admitted to hospital/ICU), seroresponses were more robust and rich with a shift towards IgG over IgA and anti-spike over anti-nucleocapsid responses. Among seropositive participants, lower antibody levels were observed for those ≥ 60 years vs < 60 years old and smokers vs non-smokers. Overweight/obese participants vs normal weight had higher antibody levels. Adolescents (13-15 years old) (n = 260) showed a seroprevalence of 11.5%, were less likely to be tested seropositive compared to their parents and had dominant anti-spike rather than anti-nucleocapsid IgG responses. Our study provides an unbiased estimate of SARS-CoV-2 seroprevalence in Catalonia and new evidence on the durability and heterogeneity of post-infection immunity.