IBTS collaboration

• Introduction
• What are the objectives of the collaboration?
• How is the surveillance carried out?
• Reports

Introduction

Since June 2021, the National Serosurveillance Programme (NSP) has been working with the Irish Blood Transfusion Service (IBTS) to provide up-to-date estimates of COVID-19 rates of infection in adult blood donors. Following consultation with the Irish Epidemiological Modelling Advisory Group (IEMAG), and recognising that the collaboration between NSP and IBTS is providing useful information to the pandemic response, it has been extended until the end of 2022.

IBTS is responsible for the collection, testing, processing and distribution of blood components and blood products to over seventy hospitals in Ireland. For more information, please visit https://www.giveblood.ie/

What are the objectives of the collaboration?

The objectives of the collaboration are:

• To measure the age- and sex-specific prevalence of antibodies (overall and due to infection, vaccination and/or infection) to SARS-CoV-2, the virus that causes COVID-19 in residual, or left-over, blood samples from blood donors aged 20+ years in Ireland
• To measure quantitative antibody levels due to infection or vaccination by age group and sex
• To monitor trends in the presence of antibodies, and to identify any reductions that might indicate waning immunity
• To use the data to inform public health interventions, including COVID-19 modelling and vaccination strategies

How is the surveillance carried out?

Blood samples are collected every fortnight from three IBTS fixed site blood donation clinics, two in Dublin and one in Cork. The target sample size per collection period is 500. Only one specimen per person per collection period is used.

The samples are then sent to the IBTS National Donor Screening Laboratory (NDSL) and the Central Pathology Laboratory (CPL) in St. James’s Hospital for COVID-19 antibodies screening. Samples are stored for the time period necessary to complete testing and then discarded as per IBTS protocol. The following data is the only information collected for each sample:

• Unlinked unique ID number
• Date of sample collection
• Age in years (at time of donation)
• Sex
• Location of donation collection clinic
• Results of antibody testing

It is not possible to link any sample used for serosurveillance to any information that may identify someone.

The data is then analysed by the HPSC SEU team, in collaboration with IBTS, in relation to the objectives set out above.

Reports

The HPSC SEU use the analysed data to produce publicly available surveillance reports. The data are also available on the Seroepidemiology of COVID-19 Data Hub. To view the HPSC Seroepidemiology of COVID-19 Data Hub, please visit https://seroepi-hpscireland.hub.arcgis.com/

All data within the reports and dashboard is aggregated and anonymised. No data is personally identifiable. The limitations of estimating seroprevalence based on specimens collected from blood donors are clearly stated.