Study across four Irish hospitals highlights importance of C-19 genomic surveillance to inform where virus has originated, how it changes over time and how it impacts on health

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Second C-19 wave in Ireland seeded by multiple viruses coming into country means key to control includes a focus on travel


(24th February 2021) In this study titled ‘Whole-genome sequencing of SARS-CoV-2 in the Republic of Ireland during Waves 1 and 2 of the pandemic’, samples were collected from 225 individuals who attended four hospitals (Beaumont, Mater, St Vincent’s and Wexford General) in the South East of Ireland during the first and second waves of C-19. Genomic sequencing was conducted across the samples, which included 134 samples (59.6%) from Wave 1 (March to June 2020) and 91 (40.4%) from Wave 2 (July to December) and these samples in turn represented 15.2% of all C-19 admissions to these hospitals during the sampling periods.

The genomic sequencing showed the following;

  • Four variants comprised 68% of variants, were detected during Wave 1
  • Of these variants, only a single sequence was detected in Wave 2
  • During Wave 2 a single variant, known to have originated in Spain, contributed to 82.3% of lineages detected
  • Phylogenetic analysis (study of evolutionary development of group of organisms or a particular characteristic of an organism) suggested multiple introductions of this variant from outside Ireland 
  • The study found no consistent association between C-19 lineages and disease severity


Speaking about the study conclusions, Paddy Mallon, Professor of Microbial Diseases, UCD School of Medicine and Consultant in Infectious Diseases, SVUH said ‘The findings from this study suggest common C-19 lineages and variants of concern can be eliminated using ‘non-pharmaceutical interventions’ such as ‘lockdowns’ and travel restrictions and can curb progressive pandemic wave re-emergence within communities.”

“Travel is a key component in our C-19 response, but travel restrictions need robust implementation in our efforts to do everything we can to protect us against new variants coming into the country. Essentially, introduction of new variants through travel puts everything we are doing to control C-19 at risk, as people can bring potentially vaccine resistance variants into the country. We also need granular knowledge as to where the variants are coming from through contributing to large-scale surveillance sequencing programmes in Europe and around the world” continued Professor Mallon.

This ’Whole-genome sequencing of SARS-CoV-2 in the Republic of Ireland during Waves 1 and 2 of the pandemic’ study ( is part of the All Ireland Infectious Diseases Cohort Study (AIID) and the Irish Coronavirus Sequencing Consortium (ICSC) which are both supported by SFI, Enterprise Ireland, and IDA Ireland COVID-19 Rapid Response Funding Call.


To set up an interview please contact Jane Curtin, Marketing and Communications Manager, UCD School of Medicine. Tel.: 087 938 0779