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

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Ross J. Harris
  • Heather J. Whitaker
  • Nick J. Andrews
  • Felicity Aiano
  • Zahin Amin-chowdhury
  • Jessica Flood
  • Ray Borrow
  • Ezra Linley
  • Shazaad Ahmad
  • Lorraine Stapley
  • Bassam Hallis
  • Gayatri Amirthalingam
  • Katja Höschler
  • Ben Parker
  • Timothy J.g. Brooks
  • Kevin E. Brown
  • Mary E. Ramsay
  • Shamez N. Ladhani


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 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). 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.

Bibliographical metadata

Original languageEnglish
Pages (from-to)162-169
JournalJournal Of Infection
Issue number5
Early online date22 Mar 2021
Publication statusPublished - 1 May 2021