Mix-and-match COVID-19 vaccines? The idea is that a person who received a previous dose of one vaccine might receive another dose from a different vaccine.

Now that the U.S. government has announced that third booster doses are on the way for Americans who have been fully vaccinated with messenger RNA vaccines, the mix-and-match possibility will likely receive more attention.

In this Motley Fool Live video recorded on Aug. 18, Motley Fool contributors Keith Speights and Brian Orelli answer a viewer's question about whether or not mix-and-match will be an option with mRNA booster doses.

Keith Speights: I know we're out of time, but Marita asks a question, "Can a person who has had both Pfizer (NYSE:PFE) vaccines get a Moderna (NASDAQ:MRNA) booster and vice versa? Also, if a person who had J&J (NYSE:JNJ) vaccine prefers the mRNA type vaccine, what are the options?"

As far as I know, Brian, it's not looking like the FDA is going to come out and say, "Mix and match." At least that's not what I've seen thus far.

Brian Orelli: Yeah. We'll have to see what the FDA ends up doing. But there's some data that suggest that Johnson & Johnson vaccine followed by a Moderna vaccine is actually better than, or just an mRNA vaccine in general is better than actually two mRNA vaccines. We'll have to wait and see exactly what data the FDA believes and then figure out the recommendations from there.

I think at some point, mixing and matching is probably almost certainly going to happen. If we're getting into a fourth booster dose, at that point, I think you're just going to go into the pharmacy or wherever you're getting your doctor's office, and you're just going to get whatever vaccine they have right now.

You don't want to ask what kind of flu vaccine you got last year and then get the same flu vaccine this year. I think that will be at that point, at some point, but I don't know if we're there yet. I don't know if the FDA is comfortable with that idea quite yet.

Speights: The long-term could be different than the near term.

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