Moderna and Pfizer found their combo shots substantially boosted levels of omicron-fighting antibodies in adults.
If the FDA ultimately agrees, Novavax's option could become the nation's fourth COVID-19 vaccine.
Pfizer shots for 5- to 11-year-olds opened in November, but only about 30% of that age group have gotten the initial two doses.
The FDA has already granted Emergency Use Authorization for the booster for the same age group.
Some parents even have urged the government to let families choose shots before all the evidence is in.
The Centers for Disease Control and Prevention says a seroprevalence study shows that most Americans have antibodies for COVID-19 infections. …
COVID-19 antibody testing is authorized by the FDA for the purposes of producing COVID-19 convalescent plasma.
Moderna said lab tests showed the booster shots now being used - half the original dose - increased by 37 times the level of antibodies.
The data is preliminary and hasn't undergone scientific review.
Under the agreement, the government will spend $375 million to buy 300 million vials of the drug.