Two of the COVID-19 vaccines that have received U.S. emergency use authorization (EUA) use messenger RNA (mRNA) technology. Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX) became the first companies to win authorization for an mRNA vaccine. Moderna (NASDAQ:MRNA) followed close on their heels. In this Motley Fool Live video, recorded on Feb. 24, 2021, contributors Keith Speights and Brian Orelli answer a viewer's question about whether there are reasons to be concerned about the safety of these new mRNA COVID vaccines.

Keith Speights: You were talking about the messenger RNA technology. One of our viewers, Eldan, mentions correctly that mRNA is a new technology. No long-term studies on side effects have been possible thus far. Any concerns about mRNA?

Brian Orelli: I think we have mRNA in our bodies, right? We produce it every day from our DNA to make proteins in our body. I'm not sure that I'm so worried about the mRNA.

I think the components of the mRNA vaccine, the rest of those things, that those will probably be a bigger concern, and they're probably what people are reacting to when they have reactions to the vaccine. They probably actually reacting to the components of the vaccine, not the mRNA itself.

I'm personally not all that worried, but because it's been tested in 30,000 people, but certainly there could be a one in a million issue. Usually, the long-term side effects are due to long-term exposure to a drug. Like Vioxx or whatever, that wasn't because people were taking Vioxx once and they were immediately having heart problems, it was because they were taking it over a long time because they were taking it for their pain.

I think I'm not so concerned with long-term side effects just because it's a one-and-done or two-and-done treatment. You're not exposed to the components of the vaccine for that long.

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