If you're keeping score, the United Kingdom now has three COVID-19 vaccines available to their citizens while the U.S. only has two. The difference is due to AstraZeneca (NASDAQ:AZN) receiving authorization in the U.K. In this Motley Fool Live video recorded on Jan. 6, 2021, Healthcare and Cannabis Bureau Chief Corinne Cardina and Fool.com writer Keith Speights discuss how soon it might be before AstraZeneca's COVID vaccine is available in the U.S.

Corinne Cardina: Speaking of catalysts, let's talk about the big news for AstraZeneca. Their vaccine which was created with the University of Oxford, it got authorization from the UK. December 30th, right before the end of the year, vaccine doses are being administered.

Now the UK has a different process from the US as we have seen, it allows them to make these decisions faster. AstraZeneca actually conducted some of its trials in the UK while it has delayed its US trials. What do we need to know about AstraZeneca? Is this authorization a sign that points toward the US also approving AstraZeneca's vaccine? I know there's still some questions about its data.

Keith Speights: I think the big question for AstraZeneca is concerning the actual regimen. When they first reported their results they came out and said that they had an average efficacy of 70%, but that average consisted of two different groups.

One group had a half dose followed by receiving a full dose about a month later. They achieved an efficacy of around 90%. The other group that was a much larger group, by the way, in the study, received a full dose followed by another full dose and their efficacy was only around 62%.

You would definitely assume AstraZeneca wanted to pursue receiving authorization for the half-dose/full-dose regimen in the U.S. Unfortunately, their U.S. study didn't include the half-dose/full-dose regimen, at least not initially. I think we're going to see a delay in AstraZeneca getting, or having the opportunity to receive emergency use authorization in the U.S.

Cardina: Absolutely we will keep an eye on developments there.