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.

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, reports Reuters.

The study, conducted by researchers at the 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.

“Our findings confirm that the rapid spread of the Omicron [variant] primarily can be ascribed to the immune evasiveness rather than an inherent increase in the basic transmissibility,” the researchers said.