Moderna (MRNA -1.22%) shares have soared by more than 768% this year. Right now, they're sitting at an all-time high. The clinical-stage biotech company was among the first to leap into the coronavirus vaccine race earlier this year, and the clinical trial data from its candidate, mRNA-1273, has been overwhelmingly positive. After the primary analysis of its phase 3 trial, Moderna's vaccine candidate was found to be 94.1% effective at preventing COVID-19.

Now, Moderna may be only days away from receiving an emergency use authorization (EUA) from the FDA for its investigational vaccine. At this point, you might have mixed feelings about getting in on this stock. You may want to buy the shares because vaccine revenue is right around the corner, but feel wary about investing at today's valuations.

An investor points to a "buy" button on a green and red chart showing stock market gains.

Image source: Getty Images.

Does this stock have room for further gains? If the FDA grants Moderna an EUA this month, the answer is "yes." The company doesn't yet have product revenue, but it aims to manufacture at least 500 million doses of mRNA-1273 next year. Based on the $15 per-dose price Moderna charged the U.S. government, that would give it $7.5 billion in revenue. Moderna may be varying its pricing according to order size and other factors, but that calculation offers at least a rough idea of the possible revenue it could derive from the vaccine.

Still, Moderna remains a high-risk bet because all of its potential revenue for the foreseeable future depends on a single (as-yet-unapproved) product. The biotech's next closest-to-market candidate is still in phase 2 studies. So, if you're a cautious investor, you might want to consider other opportunities -- or open only a small position in Moderna. But if you're an aggressive investor, consider buying this stock even at its current high. If the vaccine continues to show safety and efficacy once it's rolled out in the general population, the rewards for the company -- and investors -- could be great.