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

2021; Elsevier BV; Volume: 82; Issue: 5 Linguagem: Inglês

10.1016/j.jinf.2021.03.015

1532-2742

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,

COVID-19 Clinical Research Studies

BackgroundAntibody 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.MethodsClinical 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.FindingsIn 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).InterpretationTrends 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.