Moderna (NASDAQ:MRNA) is once again giving its investors reason to cheer. Shares of the coronavirus vaccine maker have increased more than 30% over the past five days, rising as high as $313. As a result, the company crossed into $100 billion market cap territory.

Investors may be anticipating more revenue down the road for the biotech company. That's because the health crisis is deepening once again. The highly contagious delta variant is gaining ground in the U.S. and has become the dominant strain in the country, according to the Centers for Disease Control and Prevention. And health authorities recently said 97% of hospitalized patients these days haven't been vaccinated. Against this backdrop, White House Medical Advisor Dr. Anthony Fauci made a statement that could result in more revenue for Moderna.

A person takes a selfie with a vaccination card post vaccination.

Image source: Getty Images.

Hospitalizations increase

First, a bit of data. The current seven-day average for coronavirus hospital admissions increased more than 35% from the previous seven days. And numbers have been on the rise since June 25.

Dr. Fauci told CNN that if more people don't get a jab, we'll see a "smoldering of this outbreak in our country for a considerable period of time."

This should set the stage for big revenue for Moderna, right? The idea is this statement will convince many unvaccinated individuals to receive a vaccination. Well, yes -- but we'll have to be patient. Even if the unvaccinated rush to vaccination centers, a revenue boost won't be immediate. Moderna said in May its orders so far this year represent $19.2 billion in product revenue. This includes the U.S. government's order for enough vaccine doses from Moderna (and rival Pfizer) to cover almost every American.

Right now, 59.6% of the U.S. population ages 18 and older is fully vaccinated. If the remaining 40% of the population opts for vaccination, it means the ordered doses will make their way into people's arms -- rather than hanging around on a shelf.

Bigger orders ahead?

Now, let's look at how today's situation could lead to more revenue for Moderna. If, indeed, many Americans opt for vaccination now, the government may consider even bigger orders for the future. That's because leaders will be more certain the doses actually will be used.

Last month, the U.S. ordered another 200 million Moderna doses for delivery through the first quarter of 2022. What happens now in terms of vaccination will impact how many doses are ordered beyond that point.

Individuals' decisions about the vaccine now will impact eventual orders for boosters, too -- and even vaccines for kids. Those who get the full two-dose regimen today will need a booster down the road. So, an increase in vaccinations now equals an increase in the number of booster doses needed in the future. As for the kids market, adults who go for vaccination today are likely to make the same choice for their kids tomorrow. More than 73 million individuals in the U.S. are under age 18, according to Kids Count data. So the market is significant.

Moderna is studying potential boosters in clinical trials and says one may be ready by fall. The company has asked for authorization of its vaccine in teens. And a trial in younger children is ongoing.

What does this mean for Moderna?

Growth in the delta strain and messages from leaders like Dr. Fauci will probably prompt an increase in vaccinations. And even if this increase isn't huge, it weighs in favor of bigger rather than smaller vaccine orders down the road. That means vaccine revenue next year could be even higher than it is this year.

Optimism about this great need for vaccinations now and into the future is likely to keep Moderna's share price climbing, even considering the recent gains. The stock is trading above the most optimistic Wall Street 12-month share price forecasts. And its price in relation to forward earnings estimates has climbed 53% over the past month. If you're a bargain hunter, you may wait for a bit of a pullback before jumping in.

Still, I'm bullish on Moderna for the long term. The coronavirus vaccine is a billion-dollar product. And the company has other exciting programs in the pipeline. So even if you buy at the high, you may be happy you did a few years down the road.

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.