Evaluation of the IgG antibody response to SARS CoV-2 infection and performance of a lateral flow immunoassay: cross-sectional and longitudinal analysis over 11 months.

Abstract

OBJECTIVE:

To evaluate the dynamics and longevity of the humoral immune response to SARS-CoV-2 infection and assess the performance of professional use of the UK-RTC AbC-19 Rapid Test lateral flow immunoassay (LFIA) for the target condition of SARS-CoV-2 spike protein IgG antibodies.

DESIGN:

Nationwide serological study.

SETTING:

Northern Ireland, UK, May 2020-February 2021.

PARTICIPANTS:

Plasma samples were collected from a diverse cohort of individuals from the general public (n=279), Northern Ireland healthcare workers (n=195), pre-pandemic blood donations and research studies (n=223) and through a convalescent plasma programme (n=183). Plasma donors (n=101) were followed with sequential samples over 11 months post-symptom onset.

MAIN OUTCOME MEASURES:

SARS-CoV-2 antibody levels in plasma samples using Roche Elecsys Anti-SARS-CoV-2 IgG/IgA/IgM, Abbott SARS-CoV-2 IgG and EuroImmun IgG SARS-CoV-2 ELISA immunoassays over time. UK-RTC AbC-19 LFIA sensitivity and specificity, estimated using a three-reference standard system to establish a characterised panel of 330 positive and 488 negative SARS-CoV-2 IgG samples.

RESULTS:

We detected persistence of SARS-CoV-2 IgG antibodies for up to 10 months post-infection, across a minimum of two laboratory immunoassays. On the known positive cohort, the UK-RTC AbC-19 LFIA showed a sensitivity of 97.58% (95.28% to 98.95%) and on known negatives, showed specificity of 99.59% (98.53 % to 99.95%).

CONCLUSIONS:

Through comprehensive analysis of a cohort of pre-pandemic and pandemic individuals, we show detectable levels of IgG antibodies, lasting over 46 weeks when assessed by EuroImmun ELISA, providing insight to antibody levels at later time points post-infection. We show good laboratory validation performance metrics for the AbC-19 rapid test for SARS-CoV-2 spike protein IgG antibody detection in a laboratory-based setting.

• Authors: Louise J Robertson, Julie S Moore, Kevin Blighe, Kok Yew Ng, Nigel Quinn, Fergal Jennings, Gary Warnock, Peter Sharpe, Mark Clarke, Kathryn Maguire, Sharon Rainey, Ruth K Price, William P Burns, Amanda M Kowalczyk, Agnes Awuah, Sara E McNamee, Gayle E Wallace, David Hunter, Steve Sager, Connie Chao Shern, M Andrew Nesbit, James A D McLaughlin, Tara Moore
• Journal: BMJ open (BMJ Open) Vol. 11 Issue 6 Pg. e048142 (06 29 2021) ISSN: 2044-6055 [Electronic] England
• PMID: 34187827 (Publication Type: Journal Article)
• Copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Chemical References

• Antibodies, Viral
• Immunoglobulin G
• Spike Glycoprotein, Coronavirus
• spike protein, SARS-CoV-2

Topics

• Antibodies, Viral
• Antibody Formation
• COVID-19 (therapy)
• Cross-Sectional Studies
• Humans
• Immunization, Passive
• Immunoassay
• Immunoglobulin G
• Northern Ireland (epidemiology)
• SARS-CoV-2
• Sensitivity and Specificity
• Spike Glycoprotein, Coronavirus
• COVID-19 Serotherapy