The U.S government's plan to roll out additional shots of the COVID-19 vaccine for the general public on Sept. 20 will proceed with just the Pfizer/BioNTech SE vaccine, a source familiar with the discussion said Friday.

Moderna Inc.'s initil booster submission was found inadequate and the U.S. Food and Drug Administration requires stronger data from the company, making the process likely to be a few weeks behind that of Pfizer/BioNTech, the source added.