Analysis of SARS-CoV-2 antibody seroprevalence in Northern Ireland during 2020–2021

Abstract

Background With the spread of SARS-CoV-2 impacting upon public health directly and socioeconomically, further information was required to inform policy decisions designed to limit virus spread during the pandemic. This study sought to contribute to serosurveillance work within Northern Ireland to track SARS-CoV-2 progression and guide health strategy. Methods Sera/plasma samples from clinical biochemistry laboratories were analysed for anti-SARS-CoV-2 antibodies. Samples were assessed using an Elecsys anti-SARS-CoV-2 or anti-SARS-CoV-2 S ECLIA (Roche) on an automated cobas e 801 analyser. Samples were also assessed via an anti-SARS-CoV-2 ELISA (Euroimmun). A subset of samples assessed via the Elecsys anti-SARS-CoV-2 ECLIA were subsequently analysed in an ACE2 pseudoneutralisation assay using a V-PLEX SARS-CoV-2 Panel 7 for IgG and ACE2 (Meso Scale Diagnostics). Results Across three testing rounds (June–July 2020, November–December 2020 and June–July 2021 (rounds 1–3 respectively)), 4844 residual sera/plasma specimens were assayed for anti-SARS-CoV-2 antibodies. Seropositivity rates increased across the study, peaking at 11.6 % (95 % CI 10.4 %–13.0 %) during round 3. Varying trends in SARS-CoV-2 seropositivity were noted based on demographic factors. For instance, highest rates of seropositivity shifted from older to younger demographics across the study period. In round 3, Alpha (B.1.1.7) variant neutralising antibodies were most frequently detected across age groups, with median concentration of anti-spike protein antibodies elevated in 50–69 year olds and anti-S1 RBD antibodies elevated in 70+ year olds, relative to other age groups. Conclusions With seropositivity rates of <15 % across the assessment period, it can be concluded that the significant proportion of the Northern Ireland population had not yet naturally contracted the virus by mid-2021.

Description

Publication history: Accepted - 4 January 2024; Published online - 10 January 2024.

Keywords

SARS-CoV-2, COVID-19, Seroprevalence, Public health policy, Seropositivity, Demographics

Citation

Greene, M.K., Smyth, P., English, A., McLaughlin, J., Bucholc, M., Bailie, J., McCarroll, J., McDonnell, M., Watt, A., Barnes, G., Lynch, M., Duffin, K., Duffy, G., Lewis, C., James, J.A., Stitt, A.W., Ford, T., O’Kane, M., Rai, T.S., Bjourson, A.J., Cardwell, C., Elborn, J.S., Gibson, D.S. and Scott, C.J. (2024) ‘Analysis of SARS-CoV-2 antibody seroprevalence in Northern Ireland during 2020–2021’, Heliyon. Elsevier BV. Available at: https://doi.org/10.1016/j.heliyon.2024.e24184.

DOI

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