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

Ross J. Harris, Heather Whitaker, Nicholas Andrews, Felicity Aiano, Zahin Amin-Chowdhury, Jessica Flood, Raymond Borrow, Ezra Linley, Shazaad Ahmad, Lorraine Stapley, Bassam Hallis, Gayatri Amirthalingam, Katja Hoschler, Ben Parker, Alex Horsley, Timothy J.G. Brooks, Kevin Brown, Mary Ramsay, Shamez Ladhani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Citations (Scopus)


Background: 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.

Methods: 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.

Findings: 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 everpositivity, 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).

Interpretation: 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. (C) 2021 Published by Elsevier Ltd on behalf of The British Infection Association.

Original languageEnglish
Pages (from-to)162-169
Number of pages8
JournalJournal of Infection
Issue number5
Publication statusPublished - May 2021

Bibliographical note

Publisher Copyright:
© 2021

Funding Information:
BP and AH are supported by the NIHR Manchester Biomedical Research Centre. This research was internally funded by Public Health England and carried out at by the NIHR Manchester Clinical Research Facility. The views expressed are those of the authors and not necessarily those of Public Health England, NHS, the NIHR or the Department of Health. We would like to express our gratitude to all the participants and to the laboratory staff for testing the samples. Individual-level data are confidential and cannot be shared under the agreements of the study. Requests for anonymised datasets for specific research purposes may be made to the corresponding author, and will be considered subject to an appropriate data sharing agreement.

Publisher Copyright:
© 2021


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