Here in the U.S., the Centers for Disease Control and Prevention has strengthened its recommendations to say that all U.S. adults should get a vaccine booster shot. Meanwhile, Pfizer said it will ask regulators this week to approve booster shots for 16- and 17-year-olds.

At the White House, President Biden said the Omicron variant was cause for concern, not panic. He said the White House would work with drug companies to reformulate vaccines to be more effective against the Omicron variant.

President Joe Biden: “So that we are prepared, if needed, my team is already working with officials at Pfizer and Moderna and Johnson & Johnson to develop contingency plans for vaccines or boosters, if needed.”