Moderna Inc’s coronavirus vaccine on Friday became the second to receive emergency use authorization (EUA) from the US Food and Drug Administration, welcome news to a nation with a staggering COVID-19 death toll of over 307,000 lives lost.

The FDA announced the authorization the day after the agency’s panel of outside experts endorsed its use and a week after the FDA authorized a vaccine from Pfizer Inc and German partner BioNTech SE.

The vaccine from Pfizer and BioNTech, which is based on similar technology, has been put into the arms of thousands of US healthcare workers this week in a massive nationwide rollout. Moderna injections are expected to begin in coming days.

“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 Stephen M. Hahn, M.D, said in a statement.

The speed of vaccine development is 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 US infectious disease scientist Anthony Fauci said in a statement.

Moderna said it intended to apply for full US license in 2021.

The FDA decision marks the first regulatory authorization in the world for Moderna’s vaccine and validation of its messenger RNA technology. It came less than a year after the first COVID-19 case was identified in the United States.

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

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

“Authorization of Moderna’s vaccine means we can accelerate the vaccination of frontline healthcare workers and Americans in long-term-care facilities, and, ultimately, bring a faster end to this pandemic,” US Health and Human Services Secretary Alex Azar said in a statement, noting the partnership of National Institutes of Health scientists with Moderna on the vaccine.

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.

Between the two vaccines, the United States is expecting 40 million doses before year end, enough to eventually vaccinate 20 million people, as both require two shots.

US President Donald Trump on Twitter hailed the authorization. “Congratulations, the Moderna vaccine is now available!” he wrote. The vaccine must be transported to hospitals and other centers before injections begin.

Moderna said it would deliver approximately 20 million doses to the US government this year and expected to have between 100 million and 125 million in the first quarter of next year, with 85-100 million of those for the United States.

Moderna has deals with the US government to provide a total of 200 million doses by the end of June 2021.

US hospitalizations and deaths have surged, driven by last month’s Thanksgiving holiday gatherings. Authorities have renewed restrictions and shutdowns across the country.

Public health officials have warned of Christmas and New Year’s celebrations, worried another virus surge could follow the current one that already threatens to overwhelm healthcare systems nationwide.

Even with two highly effective vaccines, practices such as social distancing and face covering will be needed for months before enough people are inoculated to curb virus transmission and eventually end the pandemic.