The European market is a major one for vaccine makers. First of all, more than 448 million people live in the European Union. At about $20 per dose for a two-dose vaccine, that represents a nearly $18 billion opportunity.

And second, the region has struggled through a vaccine shortage. Today, only 33% of the EU population have received at least one dose of a coronavirus vaccine. That means a lot of people still need vaccination.

Which company may benefit most? None other than pharmaceutical giant Pfizer (NYSE:PFE). The company just landed a massive deal with the European Commission. It will deliver 900 million vaccine doses from later this year through 2023. This is in addition to the commission's initial order for 600 million doses. These orders offer Pfizer an immediate advantage -- it has the opportunity to build a relationship with the European Union, and to show the strengths of its vaccine.

But that's not the only reason Pfizer may dominate in this major market. Below are three more.

A healthcare professional vaccinates a person in a medical office.

Image source: Getty Images.

1. A strong safety profile

Europe expected to vaccinate extensively with vaccines from AstraZeneca and Johnson & Johnson. The occurrence of rare but deadly blood clots in some vaccinated individuals put a temporary halt on use of those products earlier this spring.

Pfizer's vaccine hasn't been linked to such issues. An analysis of 490,000 adults who received the Pfizer or Moderna vaccines showed no cases of dangerous blood clots, Medscape reported. The American Heart Association and American Stroke Association conducted the review.

So, what's happening in Europe right now? Well, the European Medicines Agency later reaffirmed the safety of the AstraZeneca and J&J products, and most countries using them resumed vaccination. But some remain reticent. Denmark even excluded the two companies from its national vaccination program.

All of this could work to Pfizer's advantage. People and countries -- like Denmark -- may feel more confident about a vaccine that hasn't been associated with blood clots. This may weigh in when the European Commission places future orders. For example, through the contract with Pfizer, Europe has an option to obtain an additional 900 million doses. That would make the total order 1.8 billion doses.

2. A new storage temperature

Pfizer's biggest weakness has been its storage temperature. The company's vaccine requires ultracold temperatures, so special freezers are needed to keep it cold. And that makes it difficult to transport and store the vaccine in many locations.

But things are improving. Pfizer recently asked the U.S. Food and Drug Administration to approve a new, warmer storage temperature. And the agency did that just last week. Now, the Pfizer vaccine may be stored for as long as one month at standard refrigerator temperatures. Before this, the vaccine could be kept at refrigerator temperatures for only five days.

Pfizer is working to make the vaccine even more convenient in the future. The company has initiated a phase 3 trial of a freeze-dried formulation. The potential product could be stored in a regular refrigerator. Pfizer expects to report trial results in the second half of this year.

The new storage temperature -- and the potential for a freeze-dried product in the future -- clearly would make it easier to stock up on Pfizer doses. In countries such as France, vaccination often takes place in small pharmacies. They have refrigerators -- but they don't have freezers.

3. The ability to vaccinate teens

Pfizer just became the first company to win authorization for a COVID-19 vaccine to be used in adolescents ages 12 through 15. That's in the U.S., but the company has also filed for authorization in Europe and other countries. Pfizer says it expects additional authorizations "in the coming weeks."

Teens haven't been the most vulnerable during the pandemic. But, like everyone else, they play a role in spreading the virus; limiting coronavirus cases in teens means limiting cases in the entire population. Pfizer also is investigating its vaccine in children.

Authorizations in these populations would be another plus when it comes to gaining vaccine orders. If countries see the vaccine may be used across a broad group of people, they'll be more likely to make a significant order. Pfizer's rival Moderna and others are testing in these age groups, too. Still, Pfizer's first-to-market status may give it an edge.

Europe's big Pfizer vaccine order is a good reason to be optimistic about the pharmaceutical company's future in that market. But these other three points may solidify Pfizer's dominance -- now and into the future.

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.