Moderna (MRNA -1.75%) is the market leader in messenger RNA (mRNA) vaccines and therapeutics. The company shot to prominence during the COVID-19 crisis, as mRNA vaccines were the first COVID-19 vaccines to be discovered, begin human trials, and reach the market. Healthcare and Cannabis Bureau Chief Corinne Jurney Cardina and Fool contributor Taylor Carmichael discuss the main positive for Moderna stock. This video was recorded live on Feb. 19.

Corinne Cardina: For the next half-hour, we are going to talk about three of, what we think, are the best healthcare stocks to buy for 2021. We're going to dive into their growth opportunities, potential risks, and we'll even touch on an interesting contrarian play at the end. We're going to save room for questions. So open up the question-and-answer service called Slido on your browser or the app. Our code is mflive. Submit your questions or other people's, and we will try to get those answers at the end. But let's go ahead and dive in. We're going to start with the biggest stocks and drill down by market cap. The first one we are going to talk about, I'm sure everyone is a little bit tired of hearing about it, but it's Moderna. It's one of two vaccine makers with an authorized COVID vaccine in the US. Its market cap is almost $70 billion. The stock is up 817% over the past year. Taylor, let's talk about Moderna. I'm going to ask you for two green flags, and then we'll follow up with one yellow, red, orange flag because we want to be more optimistic than pessimistic.

Taylor Carmichael: [laughs]

Corinne Cardina: Two green, one possible caution flag just a potential risk. What do you think are two green flags for Moderna?

Taylor Carmichael: To me, Moderna is the leader in mRNA vaccines, and mRNA vaccines, we've seen over the last year, how powerful this technology is. They were the first vaccines to market. They got their vaccines out of the lab very quickly. They got them into animal trials very quickly. They were the first to get FDA emergency use authorization. Moderna -- and Pfizer (PFE -1.82%) was also in mRNA vaccines, that they got from BioNTech (BNTX -0.61%) . That's one thing about the mRNA vaccine. Very fast, you can find your molecule very quickly. You can get in the animal trials very quickly. And they had incredible efficacy rates. They had 95% efficacy rates. You can't complain about that. And people didn't know. They did not know if the technology was going to work prior to this. This has been really the best-case scenario for Moderna. We were hit with a horrible pandemic situation, and Moderna, boom, nailed it. They came out with the vaccine super quickly. It's amazing when you think about it actually because they did it within a year. Historically, 7 years, 10 years to get a drug onto the market, to find a molecule, to get it through clinical trials. To do this so quickly is really amazing. The positive there is if we have any other problems down the road, we have any other new viruses or new issues, it's going to be the mRNA vaccines that get to market first. They've already proven how quick their technology is, so that's a real big positive for Moderna investors is they're specialists in mRNA technology and COVID-19 and our experience with that, shows us that mRNA technology really works really well. That's a huge green flag. Just their success over the last year, I would say, is the Number 1 green flag for Moderna investors.

Corinne Cardina: Yeah, and I'll add on to that. It's not like the Moderna got lucky and just stumbled on the perfect cocktail of vaccine. They have an mRNA platform, that platform allows them to pretty easily go back to the drawing tables. We've seen all these coronavirus variants circulating. Should there be a problem with the vaccine, as is, it's not going to take a year to reformulate the vaccine to be effective against these new strains. Yeah, that Phase 3 data that came out in December, huge proof-of-concept for mRNA in healthcare. I will also add, I think it's a little bit of an advantage that now, people know what mRNA is. Maybe they don't understand the nitty-gritty, but just the fact that mRNA and RNA, in general, is now in the public lexicon. That's a big hurdle for a healthcare company. That will probably continue to be a tailwind. It's got that familiarity.