PEOPLE should "think a bit more carefully" about unnecessary social contacts and defer work Christmas parties amid forecasts that the highly transmissible Omicron variant will become dominant in Scotland within days.

Nicola Sturgeon said Scotland faced a "renewed and severe challenge" from an exponential rise in Covid and "may be starting to experience a potential tsunami of infections" driven by the highly mutated new strain.

To date, 110 cases of Omicron have been confirmed by genomic sequencing in Scotland but the true figure appears to exceed 1000 once other highly probable or possible cases (based on travel history and/or the presence of the S-gene dropout, a genomic marker characteristic of Omicron) are included. 

From tomorrow restrictions will be tightened to require all household contacts of anyone who tests positive for Covid - even if they are not identified as an Omicron case - to self-isolate for 10 days regardless of vaccination status.

Non-household contacts of any Covid positive case can end isolation if they receive a negative PCR result, as long as they are fully vaccinated.   

The First Minister warned that the variant was already impacting on public services, with dozens of A&E staff at Hairmyres hospital in Lanarkshire isolating following an Omicron outbreak at a Christmas party and 60 ScotRail trains cancelled due to staff shortages caused by people testing positive or isolating due to Omicron.

Ms Sturgeon stopped short of banning festive get togethers, but said the public should "think a bit more carefully about unnecessary social contacts" and that it "would be sensible to defer work Christmas parties".

However, she said anyone choosing to go ahead with social gatherings should "do so safely" by being vaccinated, testing beforehand and following all precautions such as mask wearing, ventilation, and hand hygiene. 

Current evidence indicates that later flow devices remain as effective in detecting people who are currently infectious with the Omicron strain as with Delta.

Scottish Government ministers are due to hold talks on the crisis again on Tuesday.

Asked why vaccine passports had not been extended to hospitality and leisure venues at this stage, Ms Sturgeon said that "will be one of the things we consider". 

The Scottish Government is also seeking funding from the UK Treasury which would enable it to provide financial assistance to businesses such as bars and restaurants if they have to be temporarily closed to curtail the Omicron wave.

Based on the current growth rate of the variant, Ms Sturgeon said Government epidemiologists "expect it to overtake Delta within days - maybe as early as the beginning of next week". 

It came as an evidence paper published today by the Scottish Government warned that Omicron is "transmitting rapidly within Scotland and there is strong evidence that community transmission is widespread".

HeraldScotland: The Omicron variant is expected to overtake Delta as the dominant Covid variant as early as the beginning of next week The Omicron variant is expected to overtake Delta as the dominant Covid variant as early as the beginning of next week

As of today, an estimated 15.5% of all Covid cases in Scotland are believed to be Omicron based on surveillance of the S-gene dropout marker, up from just 4% on Tuesday.

Omicron cases appear to be doubling every 2.3 days in Scotland, much faster than the seven days seen with Delta.

Early evidence also indicates that natural and vaccine-induced immunity against Omicron is weaker, and that three vaccine doses will be needed to provide substantial protection against infection - although protection against serious illness is expected to be much higher. 

Omicron was first detected in Botswana in November and has been spreading rapidly in southern Africa, including South Africa, which is now on the UK red list.

The first known cases of Omicron in Scotland were linked to a private event on November 20 involving residents from Greater Glasgow and Lanarkshire, but none had any link with overseas travel. 

Dr Gregor Smith, Scotland's chief medical officer, said the exact source of the virus into Scotland is still "completely unknown". 

The evidence paper adds: "It is highly probable that Omicron will outcompete Delta and become the dominant variant within Scotland very quickly, with the potential to cause high case numbers".

HeraldScotland: The proportion of Covid cases with the S-gene dropout - a marker of probable Omicron cases - has increased rapidlyThe proportion of Covid cases with the S-gene dropout - a marker of probable Omicron cases - has increased rapidly

Ms Sturgeon warned that even if Omicron causes milder disease - which remains unclear - the "basic and quite brutal arithmetic" of the sheer number of people projected to become infected could put the NHS under severe pressure.

Central forecasts by modellers estimate that daily Omicron infections could hit around 5000 per day by December 20.

The paper adds: "To avoid the NHS being put under severe pressure Omicron would need to be substantially less severe than Delta (either because of the characteristics of Omicron or the effectiveness of vaccination against severe disease) given the very substantial number of infections projected."

Ms Sturgeon said: "Even if a smaller percentage of people require hospitalisation, a smaller percentage of a bigger number will still result in a significant number of people who require hospital care."

More than two million people in Scotland have received a booster or third dose Covid vaccination to date, with boosters currently being rolled out to people aged 40 to 49. 

However, the bulk of cases are occurring in younger age groups and around 20% of adults aged 18 to 39 have yet to be vaccinated at all, providing the virus with a substantial reservoir for transmission which increases the risk of breakthrough infections occurring in double- or triple-vaccinated individuals.