Moderna Inc. (NASDAQ: MRNA) stock skyrocketed last year, moving over 434% on global demand for coronavirus vaccines. The question now is whether it can continue to rally higher, with or without COVID-19.

The short answer is "no." But one biotech stock very well might. We'll share that one with you further down.

You see, Moderna's first authorized product was its COVID-19 vaccine, so it struck gold off the bat.

The company's development of an effective vaccine with high efficacy rates pushed the FDA to approve it for emergency use in December of last year. Investors were ready to reward it before and after that green light.

But that might not be the best idea today.

Moderna stock currently trades at $326 per share, and many analysts agree it's overvalued. Although it's the best performing S&P 500 stock this year, don't expect more gains.

Let's talk about why one other biotech stock looks more enticing now. This company just saw profits rise 160% last quarter. And it's not slowing down...

Moderna Stock Is Past Its Prime

Developing effective vaccines to help the limit spread of the coronavirus sent companies like Moderna, Pfizer Inc. (NYSE: PFE), and Johnson & Johnson (NYSE: JNJ) skyrocketing. So far in 2021, Moderna has shot up another 210%.

It can be tempting to see a stock double or triple and then buy in. But this is exactly the wrong strategy. Moderna has already had a remarkable growth spurt. This kind of thing is unlikely to happen again... but how much does it have left in the tank?

You see, once Moderna's vaccine was approved and production began, the company signed supply agreements with countries that helped speed up commercialization. At the time, only a handful of companies had vaccines approved worldwide. And in the United States, there were three that hit the market.

These supply agreements allowed Moderna to grow from almost no revenue in 2020 to an estimated $20 billion in 2021. The vaccine was an absolute blockbuster development that turned the company from an obscure biotech firm into a billion-dollar business within two years.

Beyond research for new medications that have yet to be fully developed or approved, the COVID-19 vaccine is all Moderna has. Still, with only one product, its market cap has expanded above $130 billion.

The idea is that eventually the market will trend toward normalcy, with sales narrowed to boosters for limited high-risk populations and more competition. That could cause sales to drop after 2022.

Very few on Wall Street see future upside in Moderna stock. In fact, analysts at FactSet have the average price target over the next 12 months at $188 per share - it currently trades at $336 per share.

Although Moderna is still wheeling out vaccines, other companies are in late-stage trials with effective coronavirus vaccines as well. Some have more than just a COVID-19 vaccine to show for it.

While Moderna's streak may be cooling down, there's a particular company at the middle of a market that's on pace to be worth $456.8 billion by 2027. It has all kinds of next-generation therapies on the market and in the pipeline...

The Future of Medicine

There's a current shift in the way medications are researched and developed, and it's worth understanding in order to see why this company is slated to grow.

For the longest time, developers would isolate or combine small molecules to create an effective new compound. That's how "small-molecule drugs" combatting depression, heart disease, hepatitis, and a huge range of other conditions came about.

These drugs have achieved incredible success, but in the past few years, researchers have hit it big time with biologics.

These are still chemical molecules, just much more complex than small-molecule drugs.

To put it in layman's terms, biologics are medicines that are made in or extracted from a living cell, whether a microorganism, plant or animal cell. The monoclonal antibodies made by cloning a unique white blood cell have been especially effective in changing our own immune systems. They either stop it from attacking our own bodies or "wake it up" in cancers.

There are currently 630 trials underway to add to the 120 FDA-approved monoclonal antibodies, many of which are targeting fighting coronavirus.

The development of these drugs is a whole different challenge than synthesizing a small-molecule drug. It takes specialized equipment to keep labs in perfect condition for antibodies to grow, to filter out what's needed from the mix, and to determine they're exactly right.

Positioned to Succeed

This is where Repligen Corp. (NASDAQ: RGEN) comes into play. Repligen sells the equipment and services that biologics researchers and developers need to create more efficiently and at a lower cost.

Money Morning Defense and Tech Specialist Michael A. Robinson says Repligen is "a 'pick and shovel' vaccine play, and a critically important one, given how far supply lags demand."

The company has developed a resin that binds to a protein on the coronavirus, and it's set to begin selling it this year. Using this resin should speed up the production of COVID-19 vaccines and increase the yield.

The company also makes Protein A, a key substance needed to purify the vaccines. The protein is needed in order to grow the biologics that can attack and kill cancer cells or coronaviruses, or slow down autoimmune diseases. In fact, the company is responsible for the Protein A used in over half of the world's monoclonal antibodies.

Repligen also provides much of the equipment needed for the process. For example, it offers specialized tanks, filters, and pumps used to set up chains that can turn a single growing virus, yeast, or other cell on one end into a vaccine, a gene-therapy virus, or an antibody on the other.

Now, here's where the Repligen stock price is headed...

Repligen Has Nothing but Upside

Outside the company's growth alone, it's totally safe from the risk associated with researching new drugs and the potential adverse events that come with it. We saw Pfizer and Johnson & Johnson stagger when reports of adverse effects came out about their vaccines, which was mild compared to what could happen - one bad medicine can send a company spiraling.

It also doesn't have to deal with the trials and tribulations of getting medications approved, which is no easy task today. After years of research and development, it could take a company years to have a new drug approved. That means even more time before a company sees any sort of return on the money and time research requires.

Repligen is in a perfect place to be sheltered from risk, with products any modern physicality needs in order to develop this new age of medicine.

Over the past three years, Repligen's earnings growth has averaged 35%. It's doubled in just over two years. In its most recent quarter, the company announced per-share profits jumped an amazing 160%.

Its stock has been yielding returns for investors, too. It's up 57% from last year, and you can expect that growth to pick up now that the world is more in tune with disease and virus prevention than ever before in our lifetime.

Moderna's stock is sitting at $337 per share today, but it's just about tapped out. However, the price of $237 per share is a bargain on Repligen.