Omicron is spreading at lightning speed. Scientists are trying to figure out why
In late November, more than 110 people gathered at a crowded Christmas party at a restaurant in Oslo. Most of the guests were fully vaccinated. One had returned from South Africa just a few days earlier and was unknowingly carrying the omicron variant of SARS-CoV-2.
Ultimately, about 70% of the partygoers were infected.
Scientists who traced this super spreader event concluded it was evidence that omicron was "highly transmissible" among fully-vaccinated adults.
Just over a month later, omicron's speedy worldwide ascent now makes it abundantly clear that the party wasn't an isolated example. In country after country, the new variant has outcompeted its predecessor, the delta variant — with one case of omicron sparking at least three other new infections on average. Cases have soared to record highs in parts of Europe and now the U.S., where about half a million new infections have been recorded in a single day.
"This is a game-changing virus, especially in the vaccinated population where people have had a level of invincibility," says , a professor in the Department of
