Pfizer announced Monday that its COVID-19 vaccine candidate has been 90% effective.

In a press release, the company said that in Phase 3 trials, the vaccine has proven to promote a vaccine efficacy rate above 90% following the two-shot regimen.

The Associated Press said that while Pfizer’s announcement means the company is on track to file an application for emergency use authorization later this month, it does not mean a vaccine is “imminent” and more studies are needed.

Pfizer’s vaccine candidate began Phase 3 testing in the summer and is among a handful of vaccine candidates that could be distributed in the coming months pending FDA approval.

Phase 3 trials consist of testing about 30,000 voluntary participants in a double-blind study — meaning half of those participating receive the vaccine, and half receive a placebo. Pfizer’s vaccine requires two shots, which need to be taken 28 days apart.

According to Pfizer, 90% of those who were tested for the vaccine had developed protection against the virus seven days following the second shot.

Pfizer is already in the process of producing millions of doses of its vaccine candidate after the U.S. government agreed to pay $1.95 billion for 100 million doses of the vaccine, should it prove effective. If and when the FDA grants approval for the vaccine, it will be distributed to hospitals around the country by the U.S. military in an effort the Trump administration has dubbed “Operation Warp Speed.

Even though hundreds of thousands of doses of the Pfizer vaccine will be ready for shipment if it is approved for emergency use, it will need to be rationed in the first months of its availability. According to a playbook for “Operation Warp Speed,” essential health care workers and people in high-risk populations would have the first opportunity to get a COVID-19 vaccine. The rest of the general public will be able to get the vaccine as more doses become available later in 2021.

Pfizer was one of a handful of companies that pledged in September not to distribute their vaccine under political pressure, and would only do so if it proved to be effective in large scale trials.

Monday’s announcement sent stock market futures through the roof, as investors eyed a return to economic normalcy should Pfizer’s vaccine be given emergency approval in the coming days or weeks.

President Donald Trump also celebrated the announcement in a tweet on Monday morning.

“STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!” Trump tweeted.

In a statement, President-elect Joe Biden congratulated Pfizer on their accomplishments but warned that the fight against COVID-19 is far from over.

“I congratulate the brilliant women and men who helped produce this breakthrough and to give us such cause for hope,” Biden said in a statement. “At the same time, it is also important to understand that the end of the battle against COVID-19 is still months away. This news follows a previously announced timeline by industry officials that forecast vaccine approval by late November. Even if that is achieved, and some Americans are vaccinated later this year, it will be many more months before there is widespread vaccination in this country…Today’s announcement promises the chance to change that next year, but the tasks before us now remain the same.”

An earlier version of this story stated that Pfizer’s vaccine effort was part of “Operation Warp Speed.” However, the U.S. government made the vaccine order with Pfizer outside of “Operation Warp Speed,” meaning the government did not provide funds for research or development of the drug.