Novavax says its COVID-19 vaccine is proving safe and effective for kids as young as 12.

The Maryland-based company makes a protein-based vaccine that's been cleared for use in adults in parts of the world including Britain and Europe, and is under review in the U.S.

Novavax studied more than 2,000 U.S. kids ages 12 to 17.

The company announced Thursday that the shots were 80% effective at preventing symptomatic COVID-19, and it plans to seek expanded use of the vaccine down to age 12.

The study was done last summer when the delta variant was dominant.

The delta variant is no longer the dominant variant in the U.S. According to the Centers for Disease Control, the omicron variant makes up nearly all of the new infections.