Fauci: We did not anticipate extent of omicron's mutations

President Biden ’s chief medical adviser, Anthony Fauci , said on Sunday that while officials anticipated new coronavirus variants, they did not anticipate the extent of omicron's mutations.

“We definitely saw variants coming. I think ... what was not anticipated was the extent of the mutations in the amino acid substitutions in omicron, which is really unprecedented,” Fauci told CNN’s Jake Tapper on “State of the Union.”

“It kind of came out of nowhere, where you have a virus that has 50 mutations, 30 of which are in the spike protein and 10 or 12 of which are in the receptor-binding domain. I mean to me, that's really quite unprecedented,” he added.

Fauci noted, however, that if a virus is given ample time to replicate, it will mutate and can sometimes create new variants, such as in the case of the delta variant.

Omicron, which was first discovered in South Africa last month, has officially been spotted in 89 countries, the World Health Organization said on Saturday. It was officially detected in the United States early this month, and scientists are now racing to learn more about the variant, including how severe it could be.

Fauci on Sunday emphasized that Americans need to get vaccinated, or get COVID-19 boosters if they are eligible.

“Because when you look at omicron and what it's doing - the protection from it like a two-dose mRNA vaccine is quite good, particularly against severe disease. But when you get to omicron, the protection significantly goes down,” Fauci said. “But the good news is when you boost someone, it goes right back up, and that's the reason why there's such an emphasis on the part of all of us.”