Norway’s state epidemiologist, Frode Forland, said the sheer number of people infected at a single event added to evidence that omicron was considerably more infectious than the delta variant. 

“We don’t know if it will be more transmissible, but we suspect that is the case after the first investigations we have from South Africa, and also the spread we’ve from this outbreak in Oslo,” the told The Telegraph.  

Dr Ravlo said Oslo had had few restrictions at the time the party took place, and while Norway had imposed quarantine on newly arriving travellers from South Africa that day, the two executives believed to have brought in the infection had arrived days earlier. 

The company went beyond what was necessary by insisting everyone who attended the event was double vaccinated and everyone took an antigen test, she said, adding: “At that time, we didn’t really have that many restrictions in Oslo, so they followed the rules.”

Prof Forland, director of infectious diseases at the Norwegian Institute of Public Health, said one of his agency’s three scenarios for omicron was that it would be both very mild and very transmissible.

“That is the hope. That is the best scenario we can have,” he said. “That it’s getting minder, most people will get it, and they will get a natural immunity.”

If that were the case, it may mark the beginning of the end for the Covid pandemic, he said, adding: “It might be that it has now replicated and mutated so many times that this is the optimal position from the virus’ point of view, to spread widely and not kill the hosts. 

“That’s what we’ve seen with other diseases beforehand. And of course, then it gets into more like an endemic phase.”