Moderna's (MRNA 3.28%) reliance on its COVID-19 vaccine has worried some investors. The vaccine -- Moderna's only commercialized product -- has generated billions of dollars in earnings over the past two years. Now, though, with vaccine demand on the decline, the biotech company's revenue may look a lot different in the coming quarters.

All of this has weighed on Moderna's shares. The stock sank 29% last year, and this year, it's dropped 15% so far. But there's actually a lot going on at Moderna that should spur growth over the long term. One big sign of this? While many companies are cutting costs during these tough economic times, Moderna is expanding. Does this mean it's time to buy the stock?

The vaccine situation

First, a quick look at the coronavirus vaccine situation. Last year, Moderna generated $18.4 billion in revenue from the vaccine. This year, the company has $5 billion so far in contracts for vaccine delivery. Yes, that's a big difference. And vaccine sales in the future aren't likely to top those of pandemic times.

That said, Moderna predicts coronavirus vaccine sales will follow that of the flu market. About half of the American population gets a flu jab annually. So, this could represent a significant opportunity for recurrent revenue over time.

Meanwhile, Moderna has 48 programs in development and three candidates that represent potential blockbuster revenue over the next couple of years.

These vaccine candidates for respiratory syncytial virus (RSV), cytomegalovirus (CMV), and flu are in phase 3 trials. So they're approaching the finish line. In fact, Moderna aims to file for regulatory approval of the RSV candidate by the end of the first half of this year.

Against this backdrop, Moderna just announced efforts to expand. And Moderna has what it takes to do so. Thanks to the coronavirus vaccine, Moderna has built up $18.2 billion in cash.

Now, the company plans to hire about 2,000 employees worldwide this year. Moderna also is setting up a corporate presence on the U.S. West Coast with the opening of two new offices -- in South San Francisco and Seattle. Moderna already has five U.S. offices and a presence in 17 locations around the world.

A focus on AI

The new office in Seattle will focus on technology solutions to be used throughout the company, including artificial intelligence (AI). Moderna isn't new to AI. The biotech company has used it to optimize mRNA sequence designs needed for vaccine development, for example. Moderna's Chief Data and AI Officer Dave Johnson told MIT Sloan Management Review back in 2021 that the company was even looking to AI to help it forecast and manage the flow of calls coming into its call center.

It's clear that, with its latest expansion plan, Moderna expects significant growth ahead despite considering expected declines in vaccine sales. This is a big clue that Moderna's earnings story may just be getting started. And for another clue, we can look to the pipeline. As mentioned earlier, three products may reach commercialization over the next few years.

Moderna also has many compelling candidates in earlier-stage clinical development. The U.S. Food and Drug Administration (FDA) recently granted the company's investigational personalized cancer vaccine in combination with Merck's Keytruda breakthrough therapy designation. This is meant to speed up development and review of a potential product. The companies have reported positive data from a phase 2 trial.

So, is it time to buy Moderna? Well, it's possible Moderna stock won't take off like a rocket right away. This year of transition in the coronavirus market might even weigh on the shares. But over the long term, Moderna has what it takes to grow revenue and become a multiproduct company across treatment areas. The latest expansion plan shows Moderna believes in its future. That offers us another reason to believe in it, too.

And all of this means that, while Moderna shares are in the doldrums, today is a great time to invest in this innovative company.