The Omicron coronavirus variant is better at circumventing vaccinated peoples' immunity than the Delta variant, according to a Danish study published last week, helping explain why Omicron is spreading more rapidly.
Since the discovery of the heavily mutated Omicron variant in November, scientists have been racing to find out whether it causes less serious disease and why it appears more contagious than the previously dominating Delta variant.
A virus can be more transmissible due to a number of reasons, such as the time it lingers in the air, its ability to latch onto cells, or its evasion of the body's immune system.
Investigating nearly 12,000 Danish households in mid-December, the scientists found that Omicron was 2.7 to 3.7 times more infectious than the Delta variant among vaccinated Danes.
The study, conducted by researchers at University of Copenhagen, Statistics Denmark and Statens Serum Institut (SSI), suggests the virus is mainly spreading more rapidly because it is better at evading immunity obtained from vaccines.