Editor's Note: The below video and transcript contain an error. The first and second doses of the Novavax COVID-19 vaccine are identical, and not different as the author states below. We regret the error.

Moderna (NASDAQ:MRNA) and Pfizer (NYSE:PFE) have seized an early lead in vaccine distribution in the United States. Is it too late for that underdog biotech Novavax (NASDAQ:NVAX) to win market share? Or does it actually have some advantages in the rest of the world?

Motley Fool healthcare and cannabis bureau chief Corinne Cardina and Fool.com writer Taylor Carmichael talk about the similarities and differences between the COVID-19 vaccines. This Fool Live segment was recorded on June 18.

Corinne Cardina: Can you remind us what kind of vaccine this is? Is it one or two doses? How does it stack up to Moderna and Pfizer's mRNA vaccines?

Taylor Carmichael: Yeah. It's different than the mRNA vaccines, it's more old school, I'm going to mispronounce this word, a recombinant. [laughs] I can't pronounce this.

Cardina: Recombinant nanoparticle.

Carmichael: Nanoparticle. Thank you. It's not an mRNA vaccine. There is that differences and that's (an) important difference from the point of view of speed. The mRNA vaccine, as we've seen have been very fast. They discover the molecules very fast. They were first to market. They got it all done within a year, which is amazing. Novavax is trailing by about six months. But their vaccine does have some advantages in manufacturing. I think you're going to be able to manufacture because it's easier, it's simpler. The mRNA vaccines are more complicated. I think Pfizer's manufacturing all their stuff in-house, and Moderna, I believe, is farming it out to other people, but it's very complicated. Whereas Novavax is going be simpler. I think they're going to reach a higher number of doses ultimately, they think 2 billion. Whereas the last I heard of Moderna, I think it was one billion. Novavax may ultimately produce more vaccines and there's also distribution differences too, because Moderna's and Pfizer's has to be frozen or kept really cold. Novavax's can be kept on the shelf and it lasts longer, lasts a year, I think for the Novavax vaccine. So it has a longer shelf life. Not as quick. Those are the major differences, but the major similarities is all three of these vaccines are going after the spike protein in COVID-19 and that's really been the key for the success of the vaccine. They have a similar safety profile, and a similar efficacy profiles, very high efficacy in all three of these vaccines.

Cardina: Novavax is two doses.

Carmichael: Two doses. Yes.

Cardina: We should mention that. That's another similarity with Moderna and Pfizer. We did -- go ahead.

Carmichael: Slightly different, let me talk about it a little bit. Moderna and Pfizer basically give you two doses of the same vaccine. One dose of the vaccine and a month later another dose of the vaccine. Novavax is slightly different, the first one is the vaccine, and the second one is a Matrix-M adjuvant, which it's not the vaccine, it just increases your immunity. That's a really important part of Novavax's business, that adjuvant, and it dramatically improves the efficacy of their vaccine. People have been talking, should we just do one vaccine and skip the second one. In Novavax's case, I would strongly suggest you get both shots. You get the first one and then get the second one, it's definitely worth your time and they're free. But if you want it to work, I would get both shots.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.