Moderna's coronavirus vaccine on Friday became the second to receive emergency use authorization from the U.S. Food and Drug Administration (FDA), providing some welcome news to a country with a staggering COVID-19 death toll of over 312,000.

The FDA announced the authorization on Friday after the agency's panel of outside experts on Thursday endorsed its use. Moderna says it intends to apply for full U.S. license in 2021.

The decision marks the first regulatory authorization in the world for Moderna's vaccine and validation of its messenger RNA (mRNA) technology, less than a year after the first COVID-19 case was identified in the U.S.

The biotech company has worked with the U.S. government to prepare for the distribution of 5.9 million shots as early as this weekend.

Health Canada regulators have not yet approved Moderna's vaccine. Canada is expecting about 168,000 doses of Moderna's vaccine to be available for deployment across the country before the end of the year.

The FDA decision is based on results from a late-stage study of 30,000 volunteers that found the vaccine was nearly 95 per cent effective at preventing illness from COVID-19 with no serious safety concerns.

The authorization follows an emergency use authorization granted for a similar vaccine from Pfizer and its German partner BioNTech that has been put into the arms of thousands of U.S. health-care workers this week in a massive nationwide rollout. Pfizer-BioNTech's vaccine is the only one currently approved for use in Canada, where a national rollout is currently under way.

Moderna's shot is expected to be used in harder-to-reach locations, such as rural hospitals. The vaccine needs to be stored and shipped frozen, but does not require the ultra-cold temperatures of the Pfizer-BioNTech shot.

Once thawed, the Moderna vaccine can be kept at typical refrigerator temperatures. It is administered in two shots 28 days apart.

Moderna has deals with the U.S. government to provide 20 million doses this year and a total of 200 million doses by the end of June 2021.

"With the availability of two vaccines now for the prevention of COVID-19, the FDA has taken another crucial step in the fight against this global pandemic that is causing vast numbers of hospitalizations and deaths in the United States each day," FDA Commissioner Dr. Stephen Hahn said in a statement.

The speed of vaccine development has been hailed as a stunning scientific success, although there is some hesitancy among the public.

"It is my hope that all Americans will protect themselves by getting vaccinated when the vaccine becomes available to them. That is how our country will begin to heal and move forward," top U.S. infectious disease scientist Dr. Anthony Fauci said in a statement.