Not every investment presents a win-win scenario. However, two COVID-19 vaccine stocks certainly have. Anyone who bought shares of Moderna (NASDAQ:MRNA) or Novavax (NASDAQ:NVAX) early last year and held is sitting atop hefty gains. That's one win. The other is that both companies have been successful with their development efforts, which should help end the pandemic.

Novavax has delivered greater returns than Moderna so far, but which coronavirus stock is the better pick now?

Magnifying glass in front of two COVID-19 vaccine vials with a $100 behind them

Image source: Getty Images.

The case for Moderna

You can gauge Moderna's success by the number of doses of its COVID-19 vaccine mRNA-1273 countries around the world have already ordered. The total now tops 700 million and continues to rise.

Moderna could make close to $15 billion this year from mRNA-1273. With its market cap around $70 billion right now, that would put the company's price-to-sales (P/S) ratio at 4.7 -- well below the current average P/S multiple of 8.1 for biotech stocks. This would seem to give Moderna's shares plenty of room to run.

But will Moderna be able to generate that level of annual revenue in future years? That's the big question. Moderna CEO Stephane Bancel recently stated that he expects COVID-19 "will become a market like flu." If he's right, Moderna likely will be able to enjoy strong recurring revenue from mRNA-1273.

However, its COVID-19 vaccine isn't Moderna's only potential growth driver. The company plans to advance its cytomegalovirus (CMV) vaccine mRNA-1647 into late-stage testing this year. Moderna thinks the vaccine could achieve peak annual sales between $2 billion and $5 billion if approved. 

The biotech's pipeline also includes 11 other candidates in phase 1 or phase 2 testing. Most importantly, Moderna thinks that its messenger RNA (mRNA) technology can be used in developing vaccines and therapies for a wide range of other diseases in the future. 

The case for Novavax

Unlike Moderna, Novavax hasn't yet won authorization or approval for its COVID-19 vaccine, NVX-CoV2373. But the key word in the previous sentence is "yet." Novavax has already filed for emergency use authorization (EUA) or conditional approval in the U.K., European Union, and Canada. 

The prospects of securing these EUAs and approvals look very good. In January, Novavax reported outstanding results from a late-stage study of NVX-CoV2373 conducted in the U.K. The vaccine candidate achieved an overall efficacy of 89.3%. Its efficacy against the current prevalent strain in the U.S. was 95.6%.

Novavax is also talking with the U.S. Food and Drug Administration (FDA) about potential EUA based on its U.K. study data. In the meantime, the company is moving forward with a late-stage study of NVX-CoV2373 in the U.S. and Mexico. Results from this study should be available within the next few months.

Governments around the world have already lined up to buy NVX-CoV2373. So far, Novavax has snagged supply deals for well over 300 million doses of its COVID-19 vaccine. The company should be on track to generate revenue of over $3 billion this year. 

Novavax also hopes to win FDA approval for its promising flu vaccine NanoFlu in the near future. The vaccine could achieve peak annual sales of around $1.7 billion.

Better coronavirus stock?

My view is that Novavax will probably deliver a stronger performance this year. The company has several likely catalysts on the way, notably including EUA in the U.S. Its market cap of around $18 billion isn't nearly as scary as Moderna's market cap of over $70 billion.

Over the long term, though, I suspect that Moderna will be the better stock. The biotech's mRNA platform truly could revolutionize how diseases are treated and prevented. To get a sense of how big Moderna's opportunity could be, consider that only 4% of the more than 80 viruses discovered over the last four decades have approved vaccines in the U.S.

The bottom line is that both Novavax and Moderna could continue to be winners for investors -- and for the world. 

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.