The updated vaccines protect against the XFG strain.
U.S. regulators approved updated COVID-19 shots Wednesday but limited their use for many Americans - and removed one of the two vaccines available for young children.
The American Academy of Pediatrics said on Tuesday that children ages 6 months to 23 months should receive a COVID-19 vaccine, in contrast with federal health officials.
The suspected gunman who attacked the Centers for Disease Control and Prevention's campus on Friday may have fired many hundred rounds, law enforcement said on Tuesday.
The mRNA vaccines are credited with slowing the 2020 coronavirus pandemic.
A coalition of doctors' groups and public health organizations sued the U.S. government on Monday over the decision to stop recommending COVID-19 vaccinations for most children and pregnant women.