Serological surveillance of SARS-CoV-2: Six-month trends and antibody response in a cohort of public health workers

Ross Harris, Heather Whitaker, Nick Andrews, Felicity Aiano, Zahin Amin-Chowdhury, Jessica Flood, Ray Borrow, Ezra Linley, Shazaad Ahmad, Lorraine Stapley, Bassam Hallis, Gayatri Amirthalingam, Katja Höschler, Ben Parker, Alex Horsley, Timothy Brooks, Kevin Brown, Mary Ramsay, Shamez Ladhani

Research output: Working paperPreprint


<h4>Background</h4> Antibody waning after SARS-CoV-2 infection may result in reduction in long-term immunity following natural infection and vaccination, and is therefore a major public health issue. We undertook prospective serosurveillance in a large cohort of healthy adults from the start of the epidemic in England. <h4>Methods</h4> Clinical and non-clinical healthcare workers were recruited across three English regions and tested monthly from March to November 2020 for SARS-CoV-2 spike (S) protein and nucleoprotein (N) antibodies using five different immunoassays. In positive individuals, antibody responses and long-term trends were modelled using mixed effects regression. <h4>Findings</h4> In total, 2246 individuals attended 12,247 visits and 264 were seropositive in ≥2 assays. Most seroconversions occurred between March and April 2020. The assays showed >85% agreement for ever-positivity, although this changed markedly over time. Antibodies were detected earlier with Abbott (N) but declined rapidly thereafter. With the EuroImmun (S) and receptor-binding domain (RBD) assays, responses increased for 4 weeks then fell until week 12-16 before stabilising. For Roche (N), responses increased until 8 weeks, stabilised, then declined, but most remained above the positive threshold. For Roche (S), responses continued to climb over the full 24 weeks, with no sero-reversions. Predicted proportions sero-reverting after 52 weeks were 100% for Abbott, 59% (95% credible interval 50-68%) Euroimmun, 41% (30-52%) RBD, 10% (8-14%) Roche (N) <2% Roche (S). <h4>Interpretation</h4> Trends in SARS-CoV-2 antibodies following infection are highly dependent on the assay used. Ongoing serosurveillance using multiple assays is critical for monitoring the course and long-term progression of SARS-CoV-2 antibodies.
Original languageUndefined
Publication statusPublished - 2020

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