Moderna (MRNA 1.69%) shares skyrocketed in the early stages of the pandemic as the biotech company became one of the first to bring a vaccine to market. That vaccine went on to generate billions of dollars in earnings for Moderna, allowing the company to invest in areas to speed up drug development -- such as artificial intelligence (AI) -- and advance its pipeline.

The stock hasn't been a top performer in recent times, though, declining about 80% from its peak back in 2021. Many investors, seeing that post-pandemic vaccine sales will be much lower than early pandemic sales, have turned their backs on the stock.

What about people who already bought the shares? Those who picked up Moderna as a short-term investment might have won big or lost out -- depending on when they sold the stock.

But those who believed in Moderna back in the early days and continue holding due to the company's exciting prospects probably don't regret their investment. Let's find out how much you'd have now if you'd invested $10,000 in Moderna back in 2019.

A person smiles while receiving a vaccine.

Image source: Getty Images.

Moderna's early days

At the end of 2019, the coronavirus was just emerging and Moderna hadn't yet entered the vaccine race. The company wasn't new to mRNA technology, though, and had been developing various mRNA candidates for years. Still, Moderna hadn't yet struck the fancy of investors. The share price had advanced less than 2% in its first year of trading, and the stock generally traded for $15 to $20.

If you were one of the early believers in this innovative company and bought $10,000 worth of shares in December 2019, your investment would have soared over the following two years, climbing as much as 2,000%. The stock then began its decline, as it became clear vaccine revenue would drop significantly from early pandemic levels.

But investors who held on still are winning as the stock is up 388% since December 2019. Your $10,000 invested would have more than quadrupled in value to $48,800 today.

Even though that's a fantastic return, you still might regret that you didn't sell the shares at their high. Don't beat yourself up over that -- it's nearly impossible to time the market and buy at the lowest and sell at the highest.

That's why, when investing, it's most important to look at a company's long-term story. If there are reasons to believe the particular company will deliver growth down the road, you have a solid reason to hang onto your position.

Here's the good news for Moderna investors (or potential investors): Moderna's growth is far from over. That means the stock may have what it takes to soar again down the road -- and you could benefit by holding onto your current position or buying now and holding.

A technology that works

Why am I so confident? Moderna's vaccine not only generated significant revenue but also proved an important point: the company's mRNA technology works. The biotech may not be successful in every program, but the platform is a quality one that could produce other vaccines or treatments.

Today, Moderna is getting closer and closer to becoming a multiproduct company. Regulators are reviewing the company's respiratory syncytial virus (RSV) vaccine candidate right now, and this could become the next commercialized product -- as soon as this year. Moderna's RSV candidate faces competition, but it has the advantage of being the only one to come in a pre-filled syringe. This makes it faster and easier to administer -- a feature that could help it quickly gain market share.

Moderna's late-stage pipeline -- including respiratory vaccines, latent virus vaccines, and oncology and rare disease therapeutics -- represents potential for more than $10 billion in sales. And by 2025, Moderna, expecting to have two products on the market and three set to launch, forecasts a return to sales growth.

All of this means the company's earnings and stock price may be in the doldrums today but that probably won't be the situation for very long. Moderna has plenty of elements to build a new and lasting growth story, and this could help lift earnings and your investment in this innovative biotech over time.