Novavax's vaccine is based on an older technology that has been used for decades to combat diseases including hepatitis B and influenza.
Wednesday's decision is in addition to the earlier clearance for the protein-based vaccine as a primary two-shot regimen for those 12 years and above.
Government authorities hoped that the shot would find wider acceptance among vaccine skeptics who were unwilling to take shots from Pfizer and Moderna, who used the ground-breaking messenger RNA technology.
Novavax, however, has been struggling to boost sales of the vaccine and in August halved its full-year revenue forecast, saying it does not expect further sales of the shot in the United States this year.