The COVID-19 pandemic is creating many problems in the healthcare industry, from hospitals struggling to treat patients with the disease (and deferring elective procedures in the process) to patients foregoing necessary care. But it's also highlighting just how important, and essential, healthcare companies and drug manufacturers are right now. And one of the biggest names in the industry is Pfizer (NYSE:PFE).

Pfizer's business is undergoing many changes, and it could look very different a year from now. The company is also working on a potential vaccine for COVID-19. There are many moving parts that make it complex to assess where the company is today, where it's headed, and whether the stock is a good buy. Let's take a closer look at Pfizer and evaluate whether its stock is worth investing in.

Pfizer's coming off a tough quarter -- but it's expecting things to get better

In its second-quarter results, released July 28, the New York-based company reported $11.8 billion in revenue, a 9% decline from the prior-year period. The biopharma segment still did well, with sales rising by 4%. It was Pfizer's generics business, Upjohn, that dragged results down, as revenue there declined by 32% -- largely because it lost exclusivity to seizure medication Lyrica in 2019 . Pfizer is spinning off Upjohn, which will join Mylan in a transaction that the company expects to close in the fourth quarter.

People working in a lab.

Image source: Getty Images.

Despite the drop in revenue, the company still posted a profit of $3.4 billion during the quarter. That's down 32% from a year ago, when Pfizer's net income was over $5 billion.

However, management is optimistic that the second half of the year will be better, as COVID-19 restrictions are less severe now than they were a few months ago. Management is anticipating that more patients will be visiting their doctors and that more elective surgical procedures will take place as the year goes on.

And that's why management slightly upgraded its forecast for the year, to between $48.6 billion and $50.6 billion. Previously, Pfizer was expecting its top line to be in the slightly lower range of $48.5 billion and $50.5 billion. In 2019, Pfizer's revenue was $51.8 billion, down from $53.6 billion in the previous year.

The big question mark is how the company will do next year, without Upjohn and amid all this transition. Although the segment's sales were declining, Upjohn currently accounts for around 17% of Pfizer's top line. So, while the company's overall growth rate may actually improve, its total revenue number will likely fall.  

Positive vaccine results could make the stock a hot buy

There's lots of excitement surrounding a possible COVID-19 vaccine, and that is the one wild card that could potentially make Pfizer a great buy despite question marks about its future growth.

The company's working on a vaccine with BioNTech. On July 27, it announced the beginning of a Phase 2/3 trial that will include as many as 30,000 people. If the trial proves successful, the companies will look to obtain an emergency use authorization for the vaccine from the U.S. Food and Drug Administration (FDA) as early as October, and they could have 100 million doses available before the end of the year.

A successful COVID-19 vaccine could generate significant sales growth for Pfizer for an indefinite amount of time. That's because there's uncertainty about how long a vaccine may be effective in preventing people from contracting COVID-19. It's possible that annual vaccinations may be necessary to keep people safe. That could result in lots of recurring income for Pfizer. COVID-19 remains a problem in many countries around the world, and there would be plenty of demand for a vaccine.

Investors only need to look as far as Moderna to see how excitement surrounding a vaccine can send a stock soaring. Shares of Moderna are up about 280% since the start of the year, while the S&P 500 has risen by just 4%. Pfizer, meanwhile, is still in negative territory, down 2%.

Pfizer's stock is worth buying despite the uncertainty

It's never easy investing in a company with many unknowns, or one that's in the midst of a transition. It's likely part of the reason shares of Pfizer aren't doing so well this year. But for Foolish investors, this creates an opportunity to buy this temporarily underperforming stock while its price remains low, as there's plenty of potential for it to take off in the near future.

If the company's vaccine proves to be successful and Pfizer obtains the green light to start ramping up production, the stock will get a definite boost. At worst, it makes for a good dividend stock to hold in your portfolio; the current quarterly dividend of $0.38 yields 4% annually. And the new Pfizer will be more focused on innovation, which could mean stronger sales growth in the future.

Pfizer is a big-name health company that won't be too risky for investors over the long term. If its new business model proves successful after the transition is complete -- or if it's able to produce a successful vaccine with BioNTech -- the payoff for investors in the years to come could be significant. That's why buying shares of Pfizer today is a calculated risk that's well worth taking.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.