The changing profile of SARS-CoV-2 serology in Irish blood donors

Dermot Coyne; Dearbhla Butler; Adrienne Meehan; Evan Keogh; Pádraig Williams; Alex Carterson; Tor Hervig; Niamh O'Flaherty; Allison Waters

doi:10.1016/j.gloepi.2023.100108

The changing profile of SARS-CoV-2 serology in Irish blood donors

Glob Epidemiol. 2023 Dec:5:100108. doi: 10.1016/j.gloepi.2023.100108. Epub 2023 Apr 21.

Authors

Affiliations

¹ Irish Blood Transfusion Service, National Blood Centre, James's Street, Dublin D08 NH5R, Ireland.
² Centre for Laboratory Medicine and Molecular Pathology, St James's Hospital, James's Street, Dublin D08 NHY1, Ireland.
³ Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064, USA.
⁴ UCD National Virus Reference Laboratory, University College Dublin, Dublin 4, Ireland.
⁵ UCD School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin 4, Ireland.

Abstract

Background: The present study aimed to investigate the progression of the SARS-CoV-2 pandemic in Ireland over the first three waves of infection.

Method: A selection of blood donor serum samples collected between February 2020 and December 2021 were analysed by various commercially available serological assays for antibodies to SARS-CoV-2 (n = 15,066).

Results: An increase in seropositivity was observed between wave 1 (February to September 2020) and wave 2 (November and December 2020) of 2.20% to 3.55%. A large increase in estimated seroprevalence to 11.89% was observed in samples collected in February and March 2021 (wave 3 of infection).The rate of seropositivity varied by age group, with the highest rate observed in the youngest donors (18-29 years) peaking at 18.79% in wave 3. The results of spike antibody (anti-S) testing indicated that 44/1009 (4.36%) of seroreactive donors in wave 3 had a serological profile consistent with vaccination. By November 2021, we detected an overall seropositivity of 97.04%.

Conclusions: The present study provides a comprehensive estimation of the level of circulating SARS-CoV-2 antibodies in Irish blood donors, enabling differentiation between vaccination and natural infection, as well as real-time monitoring of the progression of the COVID-19 pandemic in Ireland. Seroepidemiology has a role in determining reliable estimates of transmission, infection fatality rates and vaccine uptake. The continued screening of blood donors for this purpose has the potential to generate important data to assist with the management of future waves of SARS-CoV-2.

Keywords: Blood; Donor; Epidemiology; Ireland; SARS-CoV-2; Serology; Vaccination.