Pfizer (PFE 1.63%) just scored another first. The company became the first to submit data to the U.S. Food and Drug Administration (FDA) that would support an authorization of its coronavirus vaccine in children under age 12. Pfizer was the first to market a coronavirus vaccine -- and the first to gain authorization for use in teens.

Pfizer plans to submit a formal request for the kids' market in the next few weeks. If the FDA gives Pfizer the nod, the company may not be alone in the market for long. Close rival Moderna also is investigating its vaccine in kids and probably will submit data to the FDA soon.

So, what does Pfizer have to do to become the leader in this market? It isn't a matter of just reaching commercialization first. In fact, there is one element that likely will determine whether Pfizer will dominate the kids' vaccine market. And this element is beyond Pfizer's control. Let's take a closer look.

A newly vaccinated child sits on the exam table in a doctor's office facing the doctor and another adult.

Image source: Getty Images.

Vaccine in children

Pfizer will request Emergency Use Authorization (EUA) of a lower-dose version of its coronavirus vaccine in children ages 5 through 11. The clinical trial included more than 2,200 participants. Pfizer recently reported favorable safety and efficacy findings. The company also plans to submit data to regulatory agencies in Europe and elsewhere.

If the FDA grants Pfizer and its partner BioNTech an EUA, the companies will find themselves with a decent market opportunity. There are more than 28 million children in the 5-11 age group in the U.S., according to Kids Count data. Each child would need two doses of vaccine. That means about 56 million vaccine doses. The U.S. most recently paid $24 a dose for Pfizer vaccines, according to The Wall Street Journal. Using that figure, an order to cover all kids in this age group amounts to more than $1.3 billion.

It's unlikely Pfizer will generate more sales immediately, however. The current U.S. supply agreement includes as many as 500 million doses to be delivered through the first quarter of next year. But if parents flock to vaccination centers with their kids, future orders could grow. The government will take a look at vaccine use before ordering future doses.

Will Pfizer own the market?

This brings us to the factor that will determine whether Pfizer will own this market -- or not. And it has to do with the number of kids who actually get vaccinated right away. Right now, things are looking a bit shaky.

About 40% of parents say they'll "wait and see" before getting their children in this age group vaccinated, according to a Kaiser Family Foundation poll. And a quarter of parents polled said they "definitely" wouldn't get their child vaccinated. Most of these parents cite concerns about long-term effects of the vaccine and near-term serious side effects, the poll showed.

On a brighter note, more than a quarter of parents surveyed said they would opt for vaccination right away. And there are plenty of anecdotal reports about parents counting the minutes until a coronavirus vaccine is available for their kids. Clearly, this population would rush to get the Pfizer vaccine.

But, for Pfizer to become the vaccine for kids, it will have to win over some of the hesitant parents -- and before rivals enter the market. Here's why: If parents are satisfied with a vaccine's performance -- especially a new vaccine -- they're very likely to go for the same one when it comes time to vaccinate again. So what happens in the coming months may determine future use of the Pfizer vaccine among kids.

Unfortunately, Pfizer doesn't have a huge amount of control over this element. The company can report thorough data and respond to parents' concerns. But in many cases, parents will put more trust in their pediatricians or even in advice from friends and family. It will be interesting to see how the situation evolves if the FDA authorizes the vaccine.

How important is this for Pfizer?

Now the big question is: How important is it for Pfizer to be on top of the kids' market? Of course, leadership here would be icing on the cake. But even without that icing, Pfizer's situation is looking good.

Pfizer and BioNTech predict more than $33 billion in revenue from the vaccine this year. The companies have signed major supply deals around the world for this year and beyond. For instance, the European Union has ordered vaccine doses through 2023.

So, even if Pfizer doesn't vaccinate the majority of kids, the company's vaccine revenue is likely to remain at major blockbuster levels. And that's why what happens in the kids' market won't make or break this healthcare stock.