Moderna (MRNA -2.53%) has been one of the top growth stories of the past year. In just 12 months, its shares have skyrocketed more than 860%, blowing past the S&P 500 and its 16% gains during that time frame. If you had bought shares of the company during the coronavirus market crash last year, you would be sitting on an incredible profit today.

The company has made a name for itself thanks to the success of its COVID-19 vaccine, MRNA-1273. And what's exciting is that Moderna's stock has the potential to climb even higher. 

COVID-19 vaccine.

Image source: Getty Images.

In March 2020, Moderna's shares were trading at about $20

During the coronavirus market crash last year, Moderna's stock fell from just under $30 a share to less than $20. At that price, a $10,000 investment in the company would have given you approximately 500 shares.

Moderna was still in the early stages of working on a vaccine for COVID-19, and betting that it would be successful was still a big risk to take. After all, back then the company didn't have much of a track record -- or any approved drugs. Investors putting money in Moderna were taking on a lot of risk.

The risk would have paid off

At a price of about $184, that $10,000 investment would now be worth approximately $92,000. That's a terrific 820% return for holding on to a stock for less than a year. It's a great example of a high-risk, high-reward investment: If the company had failed to obtain emergency use authorization (EUA) for its MRNA-1273 vaccine candidate, the stock would have flopped.

When the U.S. Food and Drug Administration (FDA) gave Moderna's candidate the thumbs-up in December 2020, its shares had already reached highs of more than $170.

Is Moderna still a good buy?

The big question is how much higher the stock can go, and whether it's worth investing in Moderna right now. The company does have other drugs in its pipeline that could generate significant sales, including mRNA-1647, which is a vaccine for cytomegalovirus (a form of herpes). Management estimates this drug has the potential to generate up to $5 billion in annual revenue at its peak. There's also its Zika vaccine, which could become a "several hundred-million-dollar annual peak sales opportunity."

But while those are promising drugs, Moderna's success for the foreseeable future will be dictated by how much of the COVID-19 market its vaccine manages to grab. That market could be worth as much as $100 billion, and right now the only approved vaccines -- from Pfizer and Moderna -- both require two doses. However, a third could soon be available, as Johnson & Johnson has requested an EUA from the FDA for its single-dose vaccine candidate. There are other companies, including Novavax, which also have vaccine candidates that could grab market share.

But right now, Moderna is ramping up production, noting that by the end of March it could hit 100 million doses. And with a price per dose of up to $37, it's easy to see how that could significantly prop up its financials. Over the past three quarters, the company has generated just $232.7 million in revenue, and that has come mainly from BARDA funding. 

It's still too early to tell how long the pandemic will drag on, and there are growing concerns that people may require annual vaccinations. Moderna is also working on booster shots for variants of COVID-19 that are emerging in various parts of the world, including South Africa and the U.K. 

There's significant sales potential for Moderna over the long term. And with a forward price-to-earnings ratio of 14, it compares well against the other healthcare stocks mentioned above:

MRNA PE Ratio (Forward) Chart

MRNA PE Ratio (Forward) data by YCharts

Moderna still looks like a promising investment. But given the uncertainty surrounding COVID-19, it likely wouldn't be suitable for risk-averse investors. 

This article represents the opinion of the writer(s), 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.