What happened

On Tuesday, investors were clearly feeling confident about Moderna's (MRNA 1.69%) looming earnings release. On the day before the high-profile biotech was to unveil its first-quarter results, its shares rose by over 3% -- thanks largely to the performance of an equally famous peer.

So what

That peer is fellow coronavirus stock Pfizer, whose results have been greatly bolstered by Comirnaty, the COVID-19 vaccine it developed with German biotech BioNTech. On Tuesday morning, Pfizer reported operational revenue growth of 82% year over year for the first quarter, and sales of Comirnaty were a key factor driving that gain.

Freshly vaccinated person giving the thumbs-up.

Image source: Getty Images.

What's good for Pfizer is good for other top COVID-19 vaccine sellers. Moderna's mRNA-1273 -- aka Spikevax -- is another go-to jab, so it absolutely fits the bill. While in the U.S., we appear to be shifting out of the intense, pandemic phase of this health crisis, the coronavirus remains a threat. With products like Spikevax and Comirnaty, we can continue to fight it effectively. 

Pfizer's ongoing strong sales of Comirnaty show that countries around the world are still eager to load up on COVID-19 shots. These products clearly have a long sales runway ahead of them.

Investors, though, should also keep in mind that Spikevax is still Moderna's only commercialized product. By contrast, Pfizer is a pharmaceutical industry powerhouse with a great many products on the market. Moderna's fortunes, for now, remain far more closely tied to demand for COVID-19 inoculations.

Now what

Moderna is scheduled to unveil its first-quarter results before the market opens on Wednesday. The company will also host an earnings call to discuss its performance.