Next steps for the Covid-19 vaccines in the US

US regulators are on the cusp of authorizing a Covid-19 vaccine -- possibly as soon as this week. A US Food and Drug Administration vaccine advisory committee meets Thursday to discuss emergency use authorization for the vaccine developed by Pfizer/BioNTech, and next week it meets to discuss the Moderna vaccine. Both vaccines are about 95% effective after two doses given a few weeks apart.

Once a vaccine is authorized by the FDA, Operation Warp Speed, the federal government's initiative to develop a vaccine, can start shipping and distributing the vaccine to states. Vaccinations won't begin until after a US Centers for Disease Control and Prevention committee recommends the vaccine.

Once shots begin, roughly 20 million people could be vaccinated in the next few weeks, Secretary of Health and Human Services Alex Azar told CNN Wednesday. But until many more are vaccinated, mitigation efforts -- such as wearing masks and keep a safe distance -- need to continue in order to stop the virus from spreading.

Here's what to expect:

Thursday, December 10

Who: FDA's Vaccines and Related Biological Products Advisory Committee, or VRBPAC -- a committee of independent experts with no stake in any of the companies developing Covid-19 vaccines

What's expected: A vote on a recommendation to the FDA on EUA for Pfizer's Covid-19 vaccine

When: 9 a.m. ET start; key testimony at 1 p.m. and 2 p.m.; Discussion/vote session starts at 3:10 p.m.; 6 p.m. end

What you'll see: Public and livestreamed remote Zoom meeting -- expect audio, slideshows, possibly some video

Draft agenda for December 10 meeting here.

Thursday, December 11 or later

Who: FDA's emergency use authorization decision

What's expected: The FDA's EUA allows shipping to begin, but shots still can't be administered until the US Centers for Disease Control and Prevention advisory committee recommends vaccine

When: FDA will announce this at any time, likely without warning.

Friday, December 11 and Sunday, December 13

Who: CDC's Advisory Committee on Immunization Practices, or ACIP

What's expected: A vote that the CDC should offer the vaccine to the American public; for recommendation to be made official, it must be accepted by CDC and published in CDC's Morbidity and Mortality Weekly Report.

When: 12 p.m.- 5 p.m. ET Friday, December 11; 12 p.m.- 4 p.m. ET Sunday, December 13; vote is currently expected at 3:30 p.m. Sunday

What you'll see: Public and livestreamed remote Zoom meeting -- expect audio, slideshows, minimal video

Draft agenda for both meetings here.

Thursday, December 17

Who: FDA VRBPAC meeting

What's expected: A vote on a recommendation to the FDA on EUA for Moderna's Covid-19 vaccine

When: Details not posted, expect it to mirror 9 a.m.- 6 p.m. ET schedule of the Pfizer meeting

What you'll see: Public and livestreamed remote Zoom meeting -- expect audio, slideshows, minimal video

Draft agenda: Not yet posted