Imprinted SARS-CoV-2 humoral immunity induces convergent Omicron RBD evolution | Nature Such rapid and simultaneous emergence of multiple variants with enormous growth advantages is unprecedented,” a Dec. 19 study in the journal Nature notes. Under selective evolutionary pressures, the virus appears to have developed mutations that enable it to transmit more easily and escape antibodies elicited by vaccines and prior infection. https://www.nature.com/articles/s41586-022-05644-7