Pfizer (PFE -1.33%) is already the leader in the coronavirus vaccine space. In the U.S. alone, it's fully vaccinated more than 127 million people. The big pharma company expects to generate $32 billion in vaccine revenue this year. Pfizer shares vaccine profits with its biotech partner, BioNTech (BNTX 2.13%).

Of course, leadership today doesn't necessarily equal leadership forever. Rival Moderna (MRNA 3.25%) has a significant position in the market. Latecomer Novavax (NVAX 0.57%) could also take market share in the months to come. Novavax sells a traditional vaccine rather than an mRNA vaccine like Pfizer and Moderna. But Pfizer and BioNTech are working on something that may be the key to long-term dominance. Let's take a look.

The challenge for vaccines

First, let's talk about the one big challenge facing today's vaccines: The emergence of variants. So far, the vaccines have held up. But efficacy has waned compared to performance against the original coronavirus. All the companies I've mentioned are working on candidates to address these variants. The latest are omicron and its subvariants.

Moderna, Pfizer, and Novavax have reported positive data from studies involving their variant-specific candidates. And Moderna even says its strain-specific booster will be ready by August. In any case, all three companies aim to make a strain-specific product available this year.

This is great news. But it's important to remember that these candidates target the current variants. What happens if a new one arises? The idea is that vaccine makers can quickly update their vaccines to fight the latest variant.

Pfizer and BioNTech, however, are working on something even better. In a recent presentation, BioNTech said the companies are developing a pan-coronavirus candidate. The idea is that this potential shot would protect against a broad range of coronavirus variants. The companies plan to bring their candidate into clinical trials in the second half of the year.

A potential game-changer

A pan-coronavirus shot could be a game-changer -- especially considering the path the virus has taken so far. Mutations aren't going away. In fact, there's evidence the virus could mutate more and more. Omicron has more sublineages than all the previous variants combined, according to BioNTech's presentation.

Today's leaders have made progress in updating their vaccines quickly. But even a matter of a few months is enough time for the virus to get ahead -- and the vaccine to fall behind. A pan-coronavirus vaccine would solve that problem.

Does this mean Moderna and Novavax could be out of the picture in a couple of years? No. Both of them are tackling another way to handle the coronavirus over the long term. They are developing combined coronavirus/flu vaccines. It's easy to imagine this sort of shot gaining market share. People who usually go for a flu shot could be the perfect audience.

But, if Pfizer is successful with its development of a pan-coronavirus vaccine, it may keep its leadership in the market. A pan-coronavirus vaccine could be the key to long-term dominance. That's because this type of product could win when it comes to efficacy. And that's likely to win over a great percentage of the population.

Of course, Pfizer still has quite a way to go, and so do Moderna and Novavax with their development of combined vaccines. Failure can happen at any point during the research and development process.

So, what does this mean for investors? Pfizer is in a position of strength in today's coronavirus market. It's important to remember Pfizer also commercializes a broad portfolio of products across many therapeutic areas. And the company has a hefty pipeline. All of this is positive. Today, Pfizer generates billions in revenue from its coronavirus program -- but unlike biotech rivals, it doesn't depend on it. Long-lasting dominance in the coronavirus market would simply be icing on the cake.