Moderna (MRNA 3.01%) was once a stock market champion. Shares of the biotech company soared more than 400% back in 2020 as investors bet on its ability to win the coronavirus vaccine race. But once Moderna actually produced the vaccine -- and brought in billions in earnings from it -- investors had already started worrying about one thing. And that was, "what's next for Moderna?"

Concerned about a potential drop in revenue post pandemic, many investors wouldn't touch Moderna stock with a 10-foot pole last year. The stock finished 2022 down 29%. But things may be changing for this vaccine giant. Let's check out why Moderna is a buy in the new year.

Billions of dollars in revenue

First, a bit of background on Moderna's place in the coronavirus vaccine market. Along with Pfizer, it's a market leader. The company brought in $18.5 billion in revenue in 2021 from its vaccine. And it expects $18 billion to $19 billion for the full year 2022. Over the past two years, Moderna and rivals have sold vaccines directly to governments. And contracts guaranteed them billions of dollars in revenue.

Moderna expects a switch to a private market this year. That means companies will sell directly to distributors instead of governments. This represents a whole new set of logistics and costs for companies. And investors may have less visibility far in advance regarding vaccine sales.

On a positive note, the price of vaccine doses could rise dramatically. Moderna has sold doses to the U.S. in the range of $15 to $26 a dose. This price could rise to about $60.

More positive news: Moderna recently provided investors with some clues about the future annual booster market. The company says the COVID-19 booster may follow the path of the flu vaccine. That could lead to a global market worth $12 billion to $24 billion -- depending on pricing of the doses.

So, yes, demand for the coronavirus vaccine surely will decline once the pandemic is over. But the product still could bring in recurrent revenue in the billions of dollars.

It's important to remember that vaccine revenue so far also has helped Moderna advance its pipeline. Moderna currently has about $17 billion in cash. This means Moderna won't be a one-product company forever. In fact, its shift to a multiproduct company may be right around the corner. That's another bright spot.

Two new vaccines on the horizon

Moderna said last year that it may launch two respiratory vaccines in the coming two to three years. The company was referring to its flu vaccine candidate and its respiratory syncytial virus (RSV) vaccine candidate. These candidates are in phase 3 trials right now. Moderna also is studying its cytomegalovirus (CMV) vaccine candidate in phase 3.

All of these represent blockbuster opportunities for Moderna. And if all continues to go smoothly, Moderna could find itself with more than one source of product revenue in just a few years.

Meanwhile, Moderna's also using its cash to support its pipeline in another way. The company just announced the acquisition of Japanese biotech OriCiro Genomics. Moderna told industry website Fierce Pharma OriCiro's cell-free DNA synthesis and amplification technologies could help cut its manufacturing time by 30%. That's a huge step toward getting products to market more quickly.

A transition point

It's hard to value Moderna using traditional methods right now. The coronavirus vaccine market is at a transition point this year. And the company will have to wait at least a couple of years for revenue from other products.

But recurring billion-dollar coronavirus booster revenue and the possibility of at least one other blockbuster product on the market down the road make Moderna look reasonably priced right now. That's why long-term investors should get in on Moderna in 2023 -- even if this isn't likely to be a big earnings year for the company. The next phase of growth may be just ahead. And early investors could eventually reap big rewards.