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Background: The seasonal human coronaviruses (HCoV) NL63, 229E, OC43, and HKU1 are globally endemic, yet the majority of HCoV infections remain undiagnosed. Methods: In a cross-sectional study, 2389 serum samples were collected from children and adults in France in 2020. In a longitudinal cohort study, 2520 samples were collected from 898 French individuals followed up between 2020 and 2021. Antibodies to HCoVs were measured using a bead-based multiplex assay. Results: The rate of waning of anti-HCoV spike immunoglobulin G antibodies was estimated as 0.22-0.47 year-1 for children, and 0.13-0.27 year-1 for adults. Seroreversion was estimated as 0.31-1.37 year-1 in children and 0.19-0.72 year-1 in adults. The estimated seroconversion rate in children was consistent with 20%-39% of children being infected every year with each HCoV. Conclusions: The high force of infection in children indicates that HCoVs may be responsible for a substantial proportion of fever episodes experienced by children.
RESUMO
BackgroundThe risk of SARS-CoV-2 (re-)infection remains present given waning of vaccine-induced and infection-acquired immunity, and ongoing circulation of new variants.AimTo develop a method that predicts virus neutralisation and disease protection based on variant-specific antibody measurements to SARS-CoV-2 antigens.MethodsTo correlate antibody and neutralisation titres, we collected 304 serum samples from individuals with either vaccine-induced or infection-acquired SARS-CoV-2 immunity. Using the association between antibody and neutralisation titres, we developed a prediction model for SARS-CoV-2-specific neutralisation titres. From predicted neutralising titres, we inferred protection estimates to symptomatic and severe COVID-19 using previously described relationships between neutralisation titres and protection estimates. We estimated population immunity in a French longitudinal cohort of 905 individuals followed from April 2020 to November 2021.ResultsWe demonstrated a strong correlation between anti-SARS-CoV-2 antibodies measured using a low cost high-throughput assay and antibody response capacity to neutralise live virus. Participants with a single vaccination or immunity caused by infection were especially vulnerable to symptomatic or severe COVID-19. While the median reduced risk of COVID-19 from Delta variant infection in participants with three vaccinations was 96% (IQR: 94-98), median reduced risk among participants with infection-acquired immunity was only 42% (IQR: 22-66).ConclusionOur results are consistent with data from vaccine effectiveness studies, indicating the robustness of our approach. Our multiplex serological assay can be readily adapted to study new variants and provides a framework for development of an assay that would include protection estimates.
