The U.S. Food and Drug Administration says the COVID-19 vaccine made by Massachusetts-based Moderna is "highly effective."
Like the vaccine by Pfizer and BioNTech that was recently approved, Moderna's vaccine requires two doses.
Moderna studies report a 94.1% efficiency rate and show that the vaccine may begin preventing infections that do not come with symptoms, known as asymptomatic infections, after the first dose. There is no public data on whether the vaccine by Pfizer and BioNTech prevents asymptomatic cases of COVID-19. Pfizer said it hopes to release data on effectiveness against such cases in early 2021.
Moderna's clinical study of its vaccine included 30,000 people ages 18 and older. The Pfizer/BioNTech vaccine study looked at people ages 16 and older.
If approved Thursday, Moderna vaccines might begin shipping this weekend. The company says it should have 20 million doses, sufficient to fully vaccinate 10 million people, ready for shipment this year.