Healthcare stocks always make a great addition to long-term portfolios. They offer you the potential to benefit from steady earnings growth over time. After all, regardless of the economic situation, people need their medicines and medical procedures.

But in this month of May, three stocks in particular make terrific buys. Two are nearing the market with much-awaited potential drugs. And one just announced a big partnership in the hot field of artificial intelligence (AI). So today marks the perfect moment to get in on these players. Let's take a close look at each.

1. Pfizer

Most of us know Pfizer (PFE -0.05%) well for one particular product -- the COVID-19 vaccine. After all, the company dominates the market and has brought in billions of dollars in revenue from the vaccine over the past two years.

But with vaccine demand on the decline, it's important to remember that Pfizer has a full portfolio of products. And even excluding contributions from its coronavirus vaccine and treatment, Pfizer's revenue climbed 5% on an operational basis in the first quarter.

In more good news, Pfizer has a new potential blockbuster on the horizon. The U.S. Food and Drug Administration (FDA) is reviewing the company's respiratory syncytial virus (RSV) vaccine candidate for older adults right now and is set to make a decision by the end of this month. Pfizer should be among the first to share a market that may top $10 billion. And the company aims to win approval of the candidate in pregnant individuals too, broadening the revenue opportunity.

The RSV candidate is just one potential new revenue driver. Pfizer expects to launch a total of 19 new products over an 18-month period. All of this should power a new wave of growth for the company.

2. Medtronic

Medtronic (MDT 0.84%) is a medical device giant, selling products in the areas of diabetes, cardiovascular, neuroscience, and surgery. These areas brought in $7.7 billion in revenue in the most recent quarter. And Medtronic has grown earnings over time.

But Medtronic's longevity doesn't make it a dinosaur. In fact, the company is on track to be a leader when it comes to using AI in healthcare. It already has integrated the technology into its products. For example, using its adaptive spine intelligence, surgeons can make early decisions for better outcomes.

Just recently, Medtronic took another step into AI, this time in the area of gastroenterology. The company will use Nvidia's Holoscan and IGX technologies in its GI Genius to widen the AI-powered tool's capabilities. Surgeons use the platform during procedures to detect precancerous tissues. Soon, thanks to the Nvidia deal, third-party developers will be able to build AI models that may eventually be added to the GI Genius.

Medtronic already is a significant player in the medical device field, but its advancements in AI could ensure leadership in many specialties down the road. And that's great news for earnings and long-term investors.

3. CRISPR Therapeutics

CRISPR Therapeutics (CRSP -1.36%) has reached an important moment. The gene-editing specialist and partner Vertex Pharmaceuticals have completed a key submission to regulators in the U.S., Europe, and the U.K. They submitted gene-editing candidate, exa-cel, for the treatment of blood disorders beta thalassemia and sickle cell disease.

This is a big deal for CRISPR because, if approved, it represents the company's first commercialized product. And it's big for a second reason too. Exa-cel uses CRISPR's gene editing, a technology the company applies across its pipeline of potential products. So, a win here would be a good sign for CRISPR's other candidates.

Regulators should decide within eight to 12 months on exa-cel. That suggests possible decisions as early as later this year and a launch soon afterward. And since treatment options are limited for beta thalassemia and sickle cell disease, doctors and patients may be eager to try exa-cel.

CRISPR shares are trading significantly lower than they were a few years ago when the company had much less visibility on potential earnings. Today, CRISPR is very close to the product finish line and has a solid pipeline too. And that makes it a top stock to buy in May for early and reasonably priced access to an exciting long-term story.