Moderna (MRNA -0.73%) has generated billions of dollars in sales and profit from its coronavirus vaccine. But the vaccine landscape is changing. As we move toward a post-pandemic world, demand is on the decline. And Moderna's vaccine isn't likely to bring in as much in revenue as it did in early pandemic days.

This doesn't mean the revenue opportunity is over, though. And the company could be heading for a big moment -- one that will give investors an idea of coronavirus vaccine revenue potential ahead. I'm talking about the fall vaccine season. Let's take a closer look at exactly how important this moment will be for Moderna.

The path so far

First, a quick summary of Moderna's path so far: The biotech company burst onto the scene with not only a coronavirus vaccine, but one that used a new technology, called messenger RNA. These types of vaccines instruct the body to produce proteins to protect itself from a particular illness -- in this case, the coronavirus. Rival Pfizer also sells an mRNA vaccine. Together, both companies dominate the vaccine market.

Last year, Moderna reported more than $19 billion in revenue and $8.4 billion in net income, thanks to the innovative vaccine -- Moderna's first and only product.

In earlier pandemic days, investors flocked to Moderna. That led the stock to more than a 400% increase back in 2020. But in recent times, investors have worried about future revenue.

Now let's talk about what's next. Moderna recently submitted its strain-specific candidate to regulators in the U.S. and Europe. Meanwhile, the company ramped up manufacturing and says it's ready to supply doses for the fall vaccination season. So, if regulators give the nod, Moderna should be well positioned to launch this updated vaccine in late August or early September.

How important is this moment for the biotech company? Well, Moderna has predicted that the coronavirus vaccine market is set to follow that of the flu market. About half of the U.S. population goes for an annual flu vaccine. We could imagine the same thing happening for the coronavirus vaccine.

Late last year, Moderna offered potential estimates for the size of the global coronavirus vaccine market. Depending on price per dose and demand, the worldwide market could be worth $8 billion to $32 billion.

A significant opportunity

This represents a significant opportunity for Moderna. And even with demand down from earlier pandemic levels, the vaccine still could deliver blockbuster revenue.

All of this means this fall clearly is important for the biotech company. But it may not completely determine Moderna's long-term coronavirus vaccine fortunes. Here's why. We haven't yet shifted into annual coronavirus vaccine mode, since people still have been getting coronavirus vaccines and boosters as needed.

So, for example, if someone just got a vaccine now, that person may not opt for a booster at the start of the vaccination season. It may take a year -- from this fall season to the following fall season -- to get people onto an annual schedule.

Also, the market is transitioning to a private one -- meaning companies will sell vaccines directly to healthcare providers rather than to the U.S. government. Moderna has said it would increase the vaccine's price to as much as $130 a dose at that time, up from today's price of about $26. It's possible this will happen in the fall, but an exact timeline hasn't been set.

So, this fall represents a transition for Moderna. But I wouldn't consider it a critical moment. That's because it probably won't represent the full vaccine picture of the future.

It will be important for Moderna to ensure smooth production and delivery of its vaccines, though -- and keep its market share in relation to Pfizer. These are the points to watch. If Moderna delivers on them, then we can consider this transition successful -- and get ready to monitor for growth in demand next year and beyond.