The initial early pandemic vaccine race came to a close long ago, but there's a new race going on -- and one that could be worth billions of dollars in recurring revenue. I'm talking about the race to develop a single product that could protect the population from flu and coronavirus. Vaccine leaders Moderna (MRNA 1.69%) and Pfizer (PFE 0.55%) are making gains in this competition, as is smaller rival Novavax (NVAX 3.54%).

All three companies are studying combined vaccines in clinical trials, and so far, the results have been promising. This week, Moderna reported the latest from its phase 1/2 study and said it was ready to start a phase 3 trial. It even said it aims to launch its combined product in 2025. Did Moderna just jump ahead of its vaccine rivals?

Pfizer in the lead

First, a little background on today's vaccine situation. Pfizer has been the leader, so far, with 65% share of the U.S. market in the first six months of this year. That's worked out fine for Moderna, though, as the company still has generated billions of dollars in revenue from its vaccine, peaking at more than $18 billion last year. 

Even though vaccine demand has declined as we head toward a post-pandemic situation, Moderna predicts vaccine sales of $6 billion to $8 billion this year. It's important to note that the company owns worldwide rights to its coronavirus vaccine and doesn't have to share profits.

Now let's turn to the combined vaccine candidate.

Novavax was the first to start talking about a combination vaccine a while back, and the company seemed to have the upper hand because it was the first to launch a development program. It also had the advantage of working with a fully developed flu vaccine candidate that already had met its phase 3 endpoints.

Today, though, Novavax is in the middle of a cost-cutting phase, which could weigh on its ability to fund the combined program -- and result in delays. Still, the company has reported positive phase 2 results so is investing step by step to prepare for late-stage development.

Moderna's cash level

Meanwhile, Moderna is flush with cash. It reached levels of more than $18 billion at the end of last year and hasn't struggled to move its programs forward. This may help it advance to commercialization more quickly than Novavax if all continues to go smoothly in the clinic.

As for Pfizer, the pharma giant began its clinical studies on a candidate late last year and said it could possibly launch a vaccine next year. This may seem overly optimistic, but it's actually possible, thanks to the use of mRNA, the key ingredient in the Pfizer and Moderna vaccines. Messenger RNA allows for speed since the sequences are quickly generated in a lab.

Still, Pfizer's candidate remains in phase 1 studies, according to the pipeline page on its website. Pfizer hasn't released details about its combined candidate's clinical trial data so it's difficult to pinpoint its progress. Moderna, about to enter phase 3, may have just stepped ahead in this important program.

What winning the race means

What does this mean for Moderna? If the company reaches commercialization first, this could be big. Such a product should easily attract those who go for annual flu shots, or about half of the U.S. population. Moderna and Pfizer both have predicted the market will mimic that of the flu -- and the possibility of one shot to cover both viruses could ensure strong vaccine uptake.

Of course, Pfizer's performance early in the vaccine race suggests this pharma giant could quickly pick up speed and deliver a product around the same time as Moderna. In fact, we may see a repeat performance of the initial coronavirus vaccine launch -- with these companies releasing their products within days of each other.

But the good news here for Moderna and its rivals is that there's room for more than one player in this market. We shouldn't forget these vaccines will be needed globally -- not just in the U.S. All of this means each vaccine maker could generate billion-dollar recurrent revenue from a combined vaccine if people do indeed go out for the shots.

That's why Moderna's progress on its combined vaccine is something to cheer about, whether the company is one step ahead of its rivals or not.