Moderna's vaccine is safe and 95 per cent effective, regulators say, clearing the way for US emergency authorisation.
If it is approved by the Food and Drug Administration's (FDA) vaccine panel, it could become the second coronavirus vaccine to be allowed in the US.
It comes one day after Americans across the country began receiving jabs of the Pfizer-BioNTech vaccine.
Unlike the Pfizer vaccine, the Moderna shot does not require ultra-cold storage during shipping.
Moderna's data was released by the FDA on Tuesday, ahead of the vaccine panel's meeting to discuss the drug on Friday.
The 54-page document said there were "no specific safety concerns" and that serious adverse reactions were rare.
If approved by the team of experts later this week, and by the FDA's vaccine chief, shipments could begin within 24 hours.
The Moderna vaccine requires temperatures of around -20C for shipping - similar to a regular freezer.
The Pfizer jab requires temperatures closer to -70C, making transport logistics much more difficult.
