It is two weeks since Chief Medical Officer Dr Tony Holohan first urged the Government to move the entire country on to Level 5 restrictions in order to suppress the second wave of Covid-19 infections.
On that occasion, the advice from the National Public Health Emergency Team (NPHET) was that the pace with which the virus was then spreading had accelerated and that all the metrics related to the virus had deteriorated.
His letter clearly stated that immediately moving the entire country up to Level 5 restrictions (from Level 2 at the time) would be the last chance to suppress the virus, while keeping schools and colleges open, protecting the most vulnerable, and maintaining non-Covid-19 health services.
During the intervening two-week period, another 12,500 Covid-19 infections were confirmed, the 14-day incidence of the virus per 100,000 people more than doubled in 19 different counties, the number of Covid-19 patients being treated in hospital went up by 122% from 134 to 298, and the reproduction (or R) number for the virus rose sharply from just over 1 to 1.6 outside of Dublin.
Every number related to the pandemic in Ireland went from bad to worse.
Professor Philip Nolan, who is the chairman of the large group of mathematical modellers that advises NPHET, outlined that the momentum behind the spread of the virus had strengthened so much that we are now likely to have between 1,800 to 2,500 new Covid-19 cases daily by the end of this month.
As each day has passed and the number of new cases grew to almost 1,300, and with two weeks still to go to the end of the month, it became clearer and clearer that the Level 3 restrictions, which the Government had instead opted for, were never going be enough.
He made it clear that much of Christmas might have to be effectively cancelled for people
Nor would the earlier recommendation from NHPET that four weeks of Level 5 restrictions for the whole country might bring the virus back under control be enough
In his most recent letter to the Government, sent last Thursday, the Chief Medical Officer upped the ante. He had already publicly announced that Halloween could not proceed as normal and that we could not have children and families going from door to door collecting on Halloween night.
But this time he made it clear that much of Christmas might have to be effectively cancelled for people if the Government did not move very quickly to Level 5 restrictions for the entire country.
Dr Holohan also made it clear that things had deteriorated so rapidly that it would now take six weeks to bring the virus back to reasonable levels in time for the festive season.
He told the Government that we are heading for having between 450 and 600 Covid-19 patients in hospital by the end of the month and that the numbers of Covid-19 patients in intensive care would triple by that date.
Before all this, NPHET had been repeatedly explaining that if people halved their social contacts then the all-important reproduction (R) number for the virus would also be halved and thereby bring the virus under control.
If the restrictions could be imposed and held in place for six weeks then the number of new cases would fall to between 50 and 100 per day by the start of December
It sounded like simple enough equation, but it was proving impossible to achieve. It had become clear that it was going to require the imposition of the highest restrictions as well as new rules and penalties to deliver the desired effect.
Dr Holohan explained in his letter last Thursday what the outcome would be if the R number was reduced to 0.5 (which is what we would achieve with a sudden lockdown) for six weeks compared to for just three weeks.
After three weeks of Level 5, he said, the expected case numbers would fall to between 250 and 300 per day, but would shoot rapidly back up to 1,000 per day by the middle of December and keep rising. That would hugely threaten our Christmas festivities.
But if the restrictions could be imposed and held in place for six weeks then the number of new cases would fall to between 50 and 100 per day by the start of December and stay low right throughout the Christmas period, before rising to about 300 per day by early January. That would save Christmas.
And that is exactly what the Government has now chosen to try to do.