Nation COVID-19 booster doses could be authorized by Friday, ‘should be a priority’ for US adults, experts say November 18, 2021 Karen Weintraub, USA TODAY Comments Off on COVID-19 booster doses could be authorized by Friday, ‘should be a priority’ for US adults, experts say The CDC said it's safe to mix vaccine brands, and data suggests Pfizer-BioNTech or Moderna would be more protective than a second J&J shot.