Omicron Variant

SARS-CoV-2 is evolving "rapidly," spawning one new variant after another. But omicron continues to dominate, raising new questions about how evolution of the virus is headed.

The COVID-19 vaccine strategy may be shifting toward Americans getting yearly vaccinations, like many do with annual flu shots.

Updated COVID boosters are now available for anyone age 12 or older. The CDC is urging anyone who is eligible to sign up but some vaccine experts say some people might want to wait.

The U.S. Food and Drug Administration authorized on Wednesday an updated formula of the COVID-19 vaccine made by Pfizer and rival Moderna, which target today’s most common omicron strain.

The omicron variant has proved adept at finding hosts, often by reinfecting people who recovered from earlier bouts of COVID. But whether omicron triggers long COVID as often and severe as previous variants is a matter of heated study.

Pfizer has submitted data on its bivalent COVID-19 booster shot that specifically targets the latest omicron subvariants. If authorized, the company says the shots could be ready as soon as September.

The president "will isolate at the White House and will continue to carry out all of his duties fully during that time," a White House statement said.

The BA.5 strain represented 65% of cases from July 3 to 9, according to data from the Centers of Disease Control and Prevention.

BA.5 is now the dominant omicron strain in the U.S. It's good at evading the immune system, though doesn't appear to cause more serious illness.

The "bivalent" vaccine — meaning it targets two different antigens — is Moderna's leading candidate to have an effective booster ready for fall of 2022, the company said.

The variants — BA.2.12 and BA.2.12.1 — have been detected in New York and other states as well as 5 other countries. One has a mutation that seems to give it an edge in evading the immune system.

Federal health officials are convening with outside advisers April 6 to talk about a vaccine plan, whether that's another booster in the fall, an omicron shot or one that targets more than one strain.