Pfizer (PFE 0.83%) and BioNTech (BNTX -0.26%) are starting to roll out their coronavirus vaccine in various countries. And Moderna (MRNA -2.31%) is hot on their heels, with regulatory approvals expected shortly. In this video from Motley Fool Live, recorded on Dec. 7, Corinne Cardina, bureau chief of healthcare and cannabis, and Fool.com contributor Brian Orelli discuss the FDA's decisions, and potential issues with the rollouts, including a manufacturing issue with Pfizer and BioNTech's vaccine.

Corinne Cardina: So turning now to the COVID-19 vaccine race, Moderna and Pfizer/BioNTech have applied for emergency use authorization from the Food and Drug Administration for their respective vaccine candidates. This Thursday, Dec. 10, an FDA advisory committee will meet to review Pfizer and BioNTech's vaccine candidate. Then on Dec. 17, it will reconvene to look at Moderna's. Of course, broadly, the advisory committee is looking at safety and efficacy -- does the vaccine prevent the disease of COVID-19? But on a more granular level, what data are these experts evaluating?

Brian Orelli: I think on safety, they're probably looking at the differences in safety for the healthy patients versus the more vulnerable patients, and are there more vulnerable patients more likely to have side effects. On efficacy, I think there are definitely going to be a big focus on the difference in the severity of the disease in patients that got vaccinated if they got the disease -- is it not very severe -- and that's obviously a big benefit. This committee has actually already met once before. Well, they meet often. They met once before specifically on coronavirus vaccines, and the big takeaway from that meeting was that the severity of the disease is very important for COVID-19, because a lot of people are getting COVID-19 and they don't have any major issues. The big takeaway was that they would like to see the vaccines lower the severity of the disease, and it seems like that's probably the case from the top-line data. Then we'd also like to see when the patients that got COVID-19, that got the vaccine, when did they get it? That will give us an idea of maybe how long it takes to be fully covered by the vaccine.

Then you mentioned the 10th and the 17th as the dates of the advisory committee meetings, but the FDA will post documents which include their review of the data, and that's for the committee members to look over for two days. That's actually coming out tomorrow. Look for that tomorrow morning, and that will be a big sign of what the FDA thinks about Pfizer's vaccine, and then a week later, we'll get the one on Moderna's. Then lastly, just as an advice, investors should remember that it's an advisory committee meeting, and so they only advise. You will see a lot of headlines on the evening after the meeting where the committee voted, but that's just an advisory voting. Just keep that in mind that the FDA has the last say.

Cardina: Excellent. We got some exciting news. Last week, the UK authorized the Pfizer-BioNTech vaccine. This week, it's expected that the first doses will be administered there, and they are beginning with care homes, both the residents and staff. How does the UK's process differ from the U.S.? Is it a positive sign that the FDA will also greenlight the Pfizer candidate?

Orelli: Yes. I'm surprised that it's such a quick approval. Not that they probably can't do it in that quick of a time, review the data. They're probably getting data in from Pfizer and BioNTech as they've been going along, so it didn't take that long to review. But I feel like people might be a little more skeptical of the speed at which it's happening, the approval process and the whole development process. So I feel like slowing down at the time and having the FDA have a committee meeting. I don't think they probably need a committee meeting. I think they probably already made up their minds. Unless there's some crazy data point that nobody has seen yet, that the FDA has seen, but the public hasn't seen, I don't think that it's likely that they'll not get authorizing. But I feel like the FDA is slowing down, and having its outside experts look at the data is helpful in terms of getting the public onboard with getting vaccinated.

Cardina: Yeah, the optics here are really important to establish that public trust. Speaking of the UK, front-line healthcare workers outside of the staff who work inside the care homes, they are actually not first in line for immunizations. In the U.S., healthcare workers, alongside home-care workers and residents, are expected to receive the vaccine first. What do you think about the discrepancy?

Orelli: I think it's crazy. They're putting their lives on the line, and they're not getting the drug first alongside the people. Obviously I don't have any problem with healthcare, with the elderly getting -- they are obviously at high risk, but so are these healthcare workers. So it seems like they should be 1A and 1B, versus 1 and 2.

Cardina: Totally. We're going to try to rapid-speed through a couple of these last COVID vaccine items, since we only have five minutes left. But let's start with Pfizer cutting its planned number of expected doses by the end of the year in half. What were the obstacles? What does this mean? Is this a sign that companies were overly optimistic in predicting the number of doses they could reasonably provide?

Orelli: Yeah. It's 50 million doses, so it's not a trivial amount of doses. The issue appears to be the ingredients in the manufacturing process. Companies not only test the final product, but they actually test all the products that go into the manufacturing process. Some of those ingredients failed, and they had to get new ones made. That seems to be the problem with the ramping up of the manufacturing process.