The major stock indexes are in the doldrums so far this year. And so are some of the most popular healthcare stocks. I'm talking about companies that have gained in the past on optimism about their programs -- or on rising revenue. But the doldrums never last forever. So, it's important to take a close look at some of today's struggling stocks. They just may be tomorrow's winners.

In fact, Wall Street analysts are pretty optimistic about three healthcare stocks that have suffered in recent times. Their average 12-month share price forecasts predict gains of more than 50% for each. Why are they so bullish on these players? Let's find out.

An investor lifts her hands in the air and smiles in front of a computer screen.

Image source: Getty Images.

1. Novavax

Novavax (NVAX 2.06%) shares surged early in the coronavirus vaccine race. They soared more than 2,700% in 2020 as Novavax developed its vaccine candidate. But when the biotech fell behind in its regulatory submission plan, the shares lost momentum. Novavax struggled to ramp up production at its manufacturing sites. Companies must prove they can produce quality vaccine at scale before winning authorization.

Since, Novavax has solved production problems -- and won authorization in more than 35 countries. The biotech also has applied for authorization in the U.S. Though Novavax has deals for vaccine delivery throughout the world, investors have focused on the upcoming U.S. regulatory decision.

A nod from the U.S. could offer shares of Novavax a boost. And if Novavax meets its goals for $4 billion to $5 billion in revenue this year, the stock could move significantly higher. Wall Street's prediction: Novavax could climb 120% in the coming 12 months.

2. Teladoc Health

Teladoc Health (TDOC -1.52%) stock was a favorite during the early days of the pandemic. People flocked to online medical appointments -- and Teladoc's visits and revenue soared in the triple digits. Since, the stock has retreated. Investors worried about a potential drop in business post pandemic, competition, and the fact that the company still isn't profitable.

But Teladoc continued to grow visits and revenue in the double digits even after the world returned to business as usual. The company's mission to treat the whole person has helped it stay ahead of rivals. And Teladoc's net loss has narrowed. The company also has set out a solid goal: more than $4 billion in revenue in 2024. And it plans to get there by increasing members and revenue per member. In the most recent quarter, it made progress in both areas.

If Teladoc continues to advance toward profit and gain in members and revenue, an investment in the stock could pay off for long-term investors. Wall Street's prediction: Teladoc shares could climb 51% over the coming 12 months.

3. CRISPR Therapeutics

CRISPR Therapeutics (CRSP -1.98%), a gene-editing company, has been a long-term winner. The stock is up more than 260% over the past five years. But in recent times, investors have taken a step back from the clinical stage company. The stock fell more than 40% over the past year.

But this isn't the time to give up on CRISPR. The company and partner Vertex Pharmaceuticals aim to file for regulatory approval of their blood disorders treatment candidate later this year. CTX001 is a one-time curative treatment for sickle cell disease and beta thalassemia. Today, treatment options for those illnesses are limited. So, victory here could be a game-changer -- for patients and for CRISPR. This could mean product revenue may be right around the corner.

CRISPR also has eight other programs in the pipeline in areas such as cancer and rare diseases. And the company is moving closer to the finish line with a second program too. Oncology candidate CTX110 is starting a pivotal trial -- data is expected this year.

It's important to note that CRISPR still comes with a certain amount of risk. Many of the company's programs are early stage. Any potential failure of an advanced program could crush hopes for near-term revenue -- and crush share performance. But positive news on CTX001 and/or CTX110 could be huge for CRISPR shares. And Wall Street agrees with this. Wall Street's prediction: The stock could soar 109% over the next 12 months.