The BA.2 sub-variant of Omicron now makes up more than 80% of coronavirus cases in Scotland and appears to have become dominant faster than in England.
The strain has a faster rate of transmission than the original version of Omicron though it is not thought to lead to more severe illness.
Nicola Sturgeon discussed the rapid spread of BA.2 during her update on Thursday, saying it was behind the recent increase in cases.
BA.2 was designated a variant under investigation towards the end of January.
Ms Sturgeon said: “The increase in cases over the past three weeks has been driven by the BA.2 sub-lineage of the Omicron variant, which is estimated to be significantly more transmissible – with a growth rate since mid-February perhaps 80% greater than original Omicron.
“BA.2 is now our dominant strain, accounting for more than 80% of all reported cases.
“BA.2 has become dominant in Scotland earlier than in England and Wales, hence the more rapid increase in cases here than south of the border in recent weeks – although cases and hospital admissions are now rising sharply again in England too.”
She said there was no evidence that BA.2 was able to escape immunity provided by vaccines or previous infections.
The fact health outcomes from Covid-19 infections are less severe than earlier in the pandemic is down to this immunity, she said.
Ms Sturgeon said: “That is borne out by current experience in Hong Kong, where relatively low rates of vaccination, particularly in the older population, mean that Omicron is causing very significant levels of severe illness and death.”
