A coronavirus vaccine candidate made by Moderna has performed with 94.5% efficacy in clinical trials, the company announced Monday. 

The drug is the second to show efficacy greater than 90% in studies backed by the U.S. government as part of its Operation Warp Speed vaccine acceleration initiative. Pfizer last week released similar findings, and both companies plan to seek emergency use authorization from the Food and Drug Administration in the coming weeks. 

Moderna’s vaccine may have a major distribution advantage over Pfizer’s candidate, according to Reuters. It can be stored at standard refrigeration temperatures for one month, a factor which could ease delivery to rural areas in particular, Matthew Hepburn, head of vaccines for Operation Warp Speed, said in a Monday briefing.

Pfizer’s vaccine, meanwhile, requires ultra-cold temperatures during shipping and storage and must be used within days once refrigerated.

Federal health officials are now considering who will get which vaccine if the two are FDA-approved, the news outlet reported. “Part of this will also be based on the distribution characteristics,” Hepburn said.

Moderna said it expects to have approximately 20 million doses of the vaccine ready to ship in the United States by the end of the year.