It found that the proportion of people who needed hospital care after getting the virus dropped from 12 per cent in January 2021 to one per cent in December.

When age was taken into account, the report said people were 12.5 times more likely to be admitted to hospital with Covid if they are unvaccinated than if they had received a booster or third vaccine dose.

Nearly two-thirds of confirmed, probable or possible omicron cases (64 per cent) recorded since the start of November were found to have been contracted by the under-40s, who have lower vaccination levels.

Despite this, the study said there had been a 31 per cent increase in hospital admissions in Scotland in the week ending December 28, with the highest number involving patients aged over 80.

The findings were based on an analysis of patient records at NHS Greater Glasgow and Clyde and NHS Grampian at the end of December and the beginning of January, with both health boards recording “reasonably similar” results.

Changing tack over omicron spread

They further increased the pressure on the First Minister over her hardline restrictions in Scotland after she admitted on Wednesday that she was rethinking her strategy for tackling Covid thanks to omicron’s increased transmissibility.

In a reversal that brings her approach more in line with England’s, she admitted that using restrictions to tackle the variant was less effective after figures showed that the proportion of Scots with the virus doubled from one in 40 to one in 20 over the festive period.

This was similar to many areas of England, where no similar measures on social distancing, licensed premises and large events including football matches were introduced.

The UK Government’s Covid dashboard on Friday showed that Scotland (2,079) had a higher case rate per 100,000 people over the previous week than England (1,787).

Dr Sandesh Gulhane, the Scottish Tories’ shadow health secretary, said that the PHS report had provided “a crucial missing piece of the puzzle through this pandemic” by disclosing four out of 10 Covid patients were not being treated primarily for the virus.

He said: “This is a significant percentage, which could mean the difference between whether restrictions are lifted or increased when it comes to decision time for the Government.”

Noting that the report covered only two of the largest health board areas, he added: “The SNP must commit to providing the full data, as soon as possible, so that we can make sure our Covid response remains balanced and proportionate in the months ahead.”