While over 11 million people in the U.S. battle cases of coronavirus, researchers have been hard at work in securing a vaccine to ward off the deadly effects of COVID-19, and as of Wednesday, Pfizer and its partner company BioNTech have announced success in this regard.

BREAKING: We are proud to announce, along with @BioNTech_Group, that the Phase 3 study of our #COVID19 vaccine candidate has met all primary efficacy endpoints.

— Pfizer Inc. (@pfizer) November 18, 2020

According to ABC News, the companies say their coronavirus vaccine is more than 95% effective in the final analysis of its massive Phase 3 trial and has reached a critical safety milestone that will allow the company to apply for Food and Drug Administration authorization “within days.”

If the FDA approves the vaccine, Pfizer is set to become the first company with an FDA-authorized COVID-19 vaccine.

The company says as soon as it has government approval, it plans to begin delivering millions of doses of the vaccine to the most vulnerable patients, possibly before the end of 2020.

Last week, Pfizer and BioNTech announced their vaccine was more than 90% effective, according to a preliminary analysis based on the first 94 patients to develop symptomatic COVID-19 in a trial of more than 43,000 volunteers.

But, ABC News reports, with the pandemic mushrooming in the United States and across the globe, it wasn't long before even more volunteers became infected. This resutled in bringing Pfizer's trial to 170 COVID-positive cases, thereby exceeding the threshold needed for a 'final' analysis on the vaccine's effectiveness.

In a press release that was issued before the stock market opened, Pfizer announced that among the 170 volunteers to develop COVID-19 in the clinical trial, 162 had been given placebo shots, while only eight volunteers to become infected were given the real vaccine.

This means Pfizer's vaccine is roughly 95% effective at preventing symptomatic COVID-19.

The updated data on the potentially life-saving drug's effectiveness follows news from competitor Moderna, which announced earlier this week that its vaccine was 94.5% effective in its own preliminary analysis.

It’s not known yet what level of immunity or how long the immunity lasts after receiving the vaccines. Trial volunteers will be followed for two years to answer questions like durability of protection.

Pfizer also announced another major milestone Wednesday, saying that it has enough safety data to merit FDA authorization.

The FDA requires at least two months of safety data among at least half of the trial volunteers before it will consider granting a limited emergency authorization, ABC News explains. Pfizer has now hit key milestones that will allow the company to apply for this limited authorization, which could happen in the coming days.

After the FDA receives Pfizer's application, it will analyze the data and assemble a panel of outside experts to offer an opinion about whether the vaccine should be authorized. Once this recommendation is received, the FDA will make its final decision.

Even if Pfizer's vaccine is authorized, the company may face challenges in the way of storage, because the Pfizer vaccine has to be stored at ultra-cold temperatures of minus 94 degrees Fahrenheit.

Pfizer has promised to publish full details from the trial through a formal scientific review process. Additional details about the trial will become available through the FDA's review process, which the agency has pledged will be transparent to the public.

Pfizer currently says it can produce 50 million vaccine doses by the end of this year, which is enough to give vaccines to 25 million people, each of whom will need two shots.

The company anticipates that it will be able to produce 1.3 billion doses globally by 2021.