The US drug regulator said Thursday it will allow the coronavirus vaccine developed by Pfizer Inc. to be transported and stored for up to two weeks at conventional freezer temperatures instead of the ultracold conditions previously required.

The U.S. added a second COVID-19 vaccine to its arsenal Friday, boosting efforts to beat back an outbreak so dire that the nation is regularly recording more than 3,000 deaths a day.

Pfizer said Friday it is asking U.S. regulators to allow emergency use of its COVID-19 vaccine, starting the clock on a process that could bring limited first shots as early as next month and eventually an end to the pandemic -- but not until after a long, hard winter.