The dynamics in the COVID-19 vaccine market continue to shift. Johnson & Johnson (JNJ -0.25%) recently won Emergency Use Authorization for its vaccine from the U.S. Food and Drug Administration. In this Motley Fool Live video, recorded on March 3, Fool.com contributors Keith Speights and Brian Orelli answer a viewer's question about how J&J's authorization could impact another leader in the COVID-19 vaccine space, Moderna (MRNA -9.07%).

Keith Speights: How does J&J's approval affect Moderna stock? What's your take on that one?

Brian Orelli: I think I saw Moderna dropped on Monday after the weekend approval. [Laughter] Which seems ridiculous both because I'm not sure that it really affects their ability to sell their vaccine. It's not going to affect their ability to sell the vaccine this year because they've already got supply agreements with the United States.

Johnson and Johnson was going to get approved. If anybody thought otherwise, they were in the very minority camp. It seems weird that it's going down and it's falling more, selling the news issue than an actual reason to justify.

Speights: I would agree. I mean, look, the news might impact the stock but it's not going to impact Moderna's business and that's the more important thing over the long run. At least it probably won't.

I guess there is that possibility that after this year if Johnson & Johnson's price is significantly lower -- they're selling it at cost right now. But after the pandemic is over, they'll want to make a profit from it. Cost could play a factor, the single-dose advantage could play a factor, but also remember the variants.

Brian, you and I have talked about this before, that the mRNA vaccines probably will be better and better positioned to respond rapidly to new variants that might emerge. That could get Moderna a leg up over Johnson & Johnson over the long run, in the COVID vaccine space anyway.