This new map could help predict the evolving paths of virus spread in the event of a future pandemic.

The study has been published in the journal Genome Medicine.

The researchers detected virus introduction events by analysing a sample of over 29,000 SARS-CoV-2 genomes (the complete set of genetic material in an organism) collected across the island of Ireland between March 2020 and June 2022. They went on to identify the origins, patterns, and frequencies of these introductions.

They also evaluated the effectiveness of public health measures, such as travel restrictions, in reducing the spread of the SARS-CoV-2 virus.

The study looked at six periods spanning the early introductions and the emergence of Alpha, Delta, and Omicron. Among 4,439 SARS-CoV-2 virus introductions to the island of Ireland, 2,535 originated in England, with additional cases largely coming from the rest of Great Britain, the United States of America, and Northwestern Europe.

The study also showed that introductions were concentrated in the densely populated Dublin and Belfast areas, with many clusters spreading island wide. Introduction rates were similar in both Northern Ireland (NI) and the Republic of Ireland (ROI) for most variants, except for Delta, which was more frequently introduced to NI. Despite this, the Delta infection rates were similar across both ROI and NI.

This finding highlights the role of internal transmission in driving infection rates and suggests that while travel restrictions reduced introductions of new Delta variants, their effect on overall infection rates was limited.

The study was led by Professor David Simpson, Professor of Genomics at the Wellcome-Wolfson Institute for Experimental Medicine at Queen’s University Belfast alongside Postdoctoral Fellows Alan M Rice and Evan P Troendle.

Professor Simpson explains: “Our findings contribute to the global understanding of how genomic surveillance can be used to track virus spread and evaluate public health interventions.

“This research will equip policymakers and health professionals with information to help them respond more effectively to future pandemics.”

The study was led by the Wellcome-Wolfson Institute for Experimental Medicine at Queen’s University Belfast, with a multidisciplinary team of researchers from the Schools of Biological Sciences, Natural and Built Environment, Pharmacy, and Medicine, Dentistry and Biomedical Sciences.

The research also involved collaboration with the Public Health Agency and the Belfast Health and Social Care Trust.

The study used data from the Global Initiative on Sharing All Influenza Data (GISAID) and benefited from membership of the COVID-19 Genomics UK (COG-UK) Consortium and collaboration with the National SARS-CoV-2 Surveillance & Whole Genome Sequencing (WGS) Programme in Ireland.

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Media inquiries to Sian Devlin at s.devlin@qub.ac.uk