The votes are in. After hours of discussion on Thursday, a key Food and Drug Administration (FDA) advisory committee has recommended that emergency use authorization (EUA) be given to BNT162b2, the COVID-19 vaccine developed by Pfizer (NYSE:PFE) and BioNTech (NASDAQ:BNTX)

It's a major milestone for both companies. It's also an enormously important step for the U.S., which lags behind Canada and the U.K. in granting emergency authorization to Pfizer's and BioNTech's vaccine. Here are the three most important things to know about the FDA advisory committee's historic vote.

Scientist holding a vaccine vial that says COVID-19 with one hand and giving a thumbs-up with the other hand

Image source: Getty Images.

1. What the committee thought about BNT162b2

Even before the FDA advisory committee's meeting started on Thursday, Harvard University immunologist and committee voting member Eric Rubin expressed enthusiasm about BNT162b2 in an editorial published yesterday morning in The New England Journal of Medicine. Rubin wrote that the development of the vaccine "is a triumph." He also stated that the results from the clinical testing performed by Pfizer and BioNTech are "impressive enough to hold up in any conceivable analysis."

Paul Offit, from The Children's Hospital of Philadelphia, said during the committee's review that "the benefits outweigh the risks" with BNT162b2. He added, "I'm fine with it." Cody Meisner, director of pediatric infectious disease at Tufts Medical Center, agreed, stating

I think the safety is pretty well demonstrated. And balance that against over 2,000 deaths a day, 2,500 deaths per day? I'm comfortable.

Pfizer's and BioNTech's data reviewed by the advisory committee showed that BNT162b2 achieved an efficacy of 52.4% after the first dose. That prompted temporary voting member and Mayo Clinic infectious disease expert Juan Gea-Banacloche to ask if a second dose is even necessary. Pfizer responded that it doesn't have sufficient data to indicate that a single dose would provide the same protection as two doses would.

In the end, the advisory committee had one question to answer: "Based on the totality of scientific evidence available, do the benefits of the Pfizer-BioNTech COVID-19 vaccine outweigh its risks for use in individuals 16 years of age and older?" And the resounding answer to that question was "yes."

2. Why the vote wasn't unanimous

The final vote for the committee was 17 in favor of recommending EUA for BNT162b2, four opposed, and one abstention. So why wasn't the vote unanimously in support of authorizing Pfizer's vaccine?

Remember that the question presented to the committee is for authorization of BNT162b2 for use in individuals ages 16 and up. There was considerable debate among the committee members about whether or not the data for study participants ages 16 and 17 were strong enough to win a positive recommendation.

Archana Chatterjee, dean of the Chicago Medical School, said that she thought that "the thinnest" data presented was for these younger participants. Chatterjee was one of the four committee members voting against recommending EUA.

3. What happens next

The FDA now must make a final decision on whether or not to grant EUA to BNT162b2. It's important to note that the agency doesn't have to accept the advisory committee's recommendation. However, the chances that the FDA will give a thumbs-up appear to be very good.

Expect a quick decision from the FDA, but just how quickly it will come remains uncertain. Health and Human Services Secretary Alex Azar has stated publicly that EUA could come "within days" of the committee's vote. 

It's possible that the FDA could choose to grant EUA to BNT162b2 only for individuals ages 18 and over after the disagreement among the advisory committee members about 16 and 17 year olds. However, that's only speculative at this point.

Assuming the FDA decides to give EUA to BNT162b2, Pfizer and BioNTech stand to rake in $1.95 billion for delivering 100 million doses of the vaccine to the U.S. government. While this windfall is already largely baked into the prices of both drug stocks, Pfizer and BioNTech should still have upside potential.

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.