So, we want to find out what the smartest investors are saying about a stock. What's one of the best ways of doing that? By playing a game. But not just any game. I'm talking about Motley Fool CAPS. It's a stock-picking game that uses the wisdom of crowds to find great investments.

Here's how it works. Players predict which stocks will beat or lag the S&P 500 over a particular time frame. CAPS then gives players ratings based on their performance versus other players. And CAPS rates stocks according to the number of players who say they'll outperform. A key point: The game weighs the opinions of highly rated players more heavily.

Motley Fool CAPS is fun, but more importantly, it can help you use the wisdom of crowds as you build or expand your portfolio. Let's give it a try with Moderna (NASDAQ:MRNA) and Novavax (NASDAQ:NVAX).

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Moderna

CAPS rating: 3 out of 5 stars

What investors might be noticing: They probably like the fact that Moderna has started generating revenue from its coronavirus vaccine. And the company expects $18.4 billion in product sales this year, according to advance purchase agreements so far. What's holding this stock back from a higher rating? Moderna shares climbed more than 400% last year; some might worry that the good news is priced in. Another concern is the vaccine's performance against new variants. Moderna says its vaccine can handle the new strains, but those tests were in vitro, not in living subjects.

Novavax

CAPS rating: 2 out of 5 stars

What investors might be noticing: Novavax has reported strong data from a phase 3 trial of its coronavirus vaccine candidate and has built an extensive manufacturing network. The biotech also has another close-to-market candidate: a potential flu vaccine. What's holding Novavax back from a better score? The stock already surged more than 2,700% last year; some worry further gains may be limited. Another concern is competition. Three other coronavirus vaccines have already entered the U.S. market. It may be difficult for Novavax to carve out a share.

The Foolish bottom line

Of the 100 highest-rated stocks on CAPS, only one has posted a negative performance over the past year. And of the six CAPS stocks that have surged more than 1,000% over the past year, four have three stars and two have five stars. So, the highest-rated stocks generally outperform over time. If we use CAPS wisdom, it looks like Moderna may be the better stock for 2021.

Should you invest $1,000 in Novavax, Inc. right now?

Before you consider Novavax, Inc., you'll want to hear this.

Investing legends and Motley Fool Co-founders David and Tom Gardner just revealed what they believe are the 10 best stocks for investors to buy right now... and Novavax, Inc. wasn't one of them.

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