Coronavirus may have been spreading in Scottish communities in February “even before the first cases emerged”, the chief medical officer has said.
Dr Gregor Smith highlighted “cutting edge” scientific work which showed a number of early cases with no link to travel from initial virus hotspots like China or Italy.
He said this suggested there had been transmission in the community in February – the month before any Scottish cases were officially confirmed – although these cases would have been “few in number”.
The CMO said scientists had identified at least 112 separate introductions of Covid-19 to Scotland which ultimately resulted in “sustained community transmission”.
Scotland’s leading medical official also insisted a Nike conference held in Edinburgh in late February which saw an early coronavirus outbreak caused no wider spike in cases in Scotland.
The first case of the virus in Scotland was officially confirmed in the Tayside area on March 1, while the first example of community transmission was announced on March 1.
Speaking at the Scottish Government’s daily Covid briefing on Tuesday, Dr Smith highlighted “next-generation sequencing technology” which allowed scientists to create “family trees” to track different local outbreaks of Covid.
Its use had enabled the government “to identify at least 112 separate introductions of Covid-19 across Scotland that ultimately led to sustained community transmission”, he said.
The CMO continued: “It has identified viral lineages with no clear link to travel at the very early stages of the outbreak in Scotland, suggesting that there may have been earlier introduction to Scotland and community spread even before the first cases emerged.
“In this respect, the emergence of continental Europe as the global epicentre of the epidemic appears to have been the main source of the particular lineages that have established in Scotland.”
The “viral lineage” linked to the Nike conference oubtreak “has not been detected in Scotland since towards the end of March”, Dr Smith said.
“This suggests that the actions taken to manage this outbreak were successful in containing spread and have led to the eradication of this particular viral lineage, with no evidence of any wider outbreak associated with it in Scotland since that time”, he added.
He defended the contact tracing process that had followed the event in the Scottish capital on February 26 and 27 as “successful” in controlling the spread of the virus.
The Scottish Government has faced criticism over claims some people who came into close contact with conference delegates were never traced by public health officials.