Every week, a report that gives a strong indication as to whether the proportion of Covid variants present in Ireland is stable or changing is sent to Dr Cillian De Gascun, the Director of the National Virus Reference Laboratory.
For months, it’s been broadly stable, in that more than 90% of cases each week were showing up as the UK, or Alpha, variant.
The report is on what’s called S-gene positivity, which indicates whether a positive Covid-19 swab contains or does not contain the Alpha variant.
What it does not do is say which other variants are present, if the Alpha variant is not there. That requires whole-genome sequencing, a process that takes up to two-and-a-half weeks.