Pfizer said Monday that an early peek at the data on its coronavirus vaccine suggests the shots may be a surprisingly robust 90% effective at preventing COVID-19, putting the company on track to apply later this month for emergency-use approval from the Food and Drug Administration.

The announcement, less than a week after a presidential election that was seen as a referendum on President Donald Trump's handling of the crisis, was a rare and major piece of encouraging news lately in the battle against the scourge that has killed more than 1.2 million people worldwide, including almost a quarter-million in the United States alone. Confirmed cases in the U.S. were expected to eclipse 10 million on Monday, the highest in the world.

“We’re in a position potentially to be able to offer some hope,” Dr. Bill Gruber, Pfizer’s senior vice president of clinical development, told The Associated Press. “We’re very encouraged.”

Dr. Anthony Fauci, the government's top-infectious disease expert, said the results suggesting 90% effectiveness are “just extraordinary," adding: "Not very many people expected it would be as high as that.”

“It’s going to have a major impact on everything we do with respect to COVID,” Fauci said.

Pharmaceutical companies and various countries are in a global race to develop a vaccine against the virus. Fauci said that the Pfizer vaccine and virtually all others in testing target the spike protein the coronavirus uses to infect cells, so the results validate that approach.

Monday's announcement doesn't mean for certain that a vaccine is imminent: This interim analysis, from an independent data monitoring board, looked at 94 infections recorded so far in a study that has enrolled nearly 44,000 people in the U.S. and five other countries. Some participants got the vaccine, while others got dummy shots.

Pfizer Inc. did not provide any more details about those infections and cautioned that the initial protection rate might change by the time the study ends. Even revealing such early data is highly unusual.

Whenever any vaccine arrives, initial supplies will be scarce and rationed, with priority likely to be given to health care workers and others on the front lines. Pfizer has estimated that 50 million doses of its vaccine could be available globally by the end of the year, which could cover 25 million people, since it is given in two doses.

“We need to see the data, but this is extremely promising,” said Dr. Jesse Goodman of Georgetown University, former chief of the FDA's vaccine division. He ticked off many questions still to be answered, including how long the vaccine's effects last and whether it protects older people as well as younger ones.

Marylyn Addo, head of the tropical medicine unit at UKE hospital in Hamburg, Germany, said the interim results were “an interesting first signal,” but questions remain.

Global markets, already buoyed by the victory of President-elect Joe Biden, exploded on the news from Pfizer. Major markets in Europe, where infections have soared, were up 5%. In the U.S., the S%P 500 surged 3.7% after the opening bell, and the Dow Jones Industrial Average was up more than 1,300 points.

Trump, who had suggested during the presidential campaign that a vaccine could be ready by Election Day, tweeted on Monday: “STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!”

The timing is likely to feed unsubstantiated suspicions from Trump supporters that the pharmaceutical industry was withholding the news until after the election. Donald Trump Jr. tweeted: “The timing of this is pretty amazing. Nothing nefarious about the timing of this at all right?"

Biden issued a statement saying: “Last night, my public health advisors were informed of this excellent news. I congratulate the brilliant women and men who helped produce this breakthrough and to give us such cause for hope.

“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,” Biden said.

Pfizer Chairman and CEO Albert Bourla said on CNBC that the election was always an artificial deadline and that the data was going to be ready when it was ready. The independent data monitors met on Sunday, analyzing the COVID-19 test results so far and notifying Pfizer.

“I am very happy," Bourla said, "but at the same time, sometimes I have tears in my eyes when I realize that this is the end of nine months, day-and-night work of so many people and how many people, billions, invested hopes on this.”

He added: “I never thought it would be 90%."

Earlier this year, Fauci said he would be happy with a COVID-19 vaccine that was 60% effective. Scientists have warned for months that any COVID-19 shot may be only as good as flu vaccines, which are about 50% effective and require yearly shots.

Pfizer opted not to join the Trump administration’s Operation Warp Speed, which helped a half-dozen drugmakers accelerate their vaccine testing and helped fund the work. Instead, Pfizer funded all its testing and manufacturing costs itself. The company said it has invested billions of dollars.

The coronavirus shots, made by Pfizer and its German partner BioNTech, are among 10 possible vaccine candidates in late-stage testing around the world — four of them so far in huge studies in the U.S. Another U.S. company, Moderna Inc., also has said it hopes to be able to file an application with the FDA later this month.

Volunteers in the final-stage studies, and the researchers, don't know who received the real vaccine or a dummy shot. But a week after their second required dose, Pfizer's study began counting the number who developed COVID-19 symptoms and were confirmed to have the coronavirus.

Spectrum News National Health Reporter Erin Billups followed up with Dr. Mark Mulligan, director of NYU Langone Health’s Vaccine Center and the principal investigator for its Pfizer and BioNTech’s COVID-19 vaccine trial.

Mulligan says the vast majority of COVID-19 infections were found among those in the placebo group.

“At the time of this interim analysis, 94 had developed a laboratory confirmed covid infections after the second vaccination, when the full immune response from the second vaccine would have been present. Those are considered primary endpoints,” Mulligan said.

Phase 3 of the study is still in progress so the exact number of those with coronavirus in the placebo group versus those given the vaccine has not been released.

Pfizer doesn’t plan to stop its study until it records 164 infections among all the volunteers, a number that the FDA has agreed is enough to tell how well the vaccine is working. The agency has made clear that any vaccine must be at least 50% effective.

Both the Moderna and Pfizer vaccines are built on a relatively new mRNA platform which has never been licensed for human use. Mulligan says the vaccine has proven very safe in phase 1 and 2 trials. In general he says RNA vaccines have been tested over the past several years against many other infectious diseases and cancer. “This type of vaccine has been investigated quite a bit in human safety and efficacy trials, so that laid the ground to hit the ground running and move fast when the covid emergency hit.”

So far, no participants have become severely ill. A breakdown of how many infections occurred among older participants is also not available yet. Mulligan says adverse reactions to the vaccine are significant, but not dangerous.

“There'll be some achiness, there might be some fever. That's to be expected more with the second dose than the first dose for both the RNA vaccines. I think it's fine, what I tell my study participants is it's probably a good thing, it means your body is reacting to the vaccine the way we want it to. And it's really something you get over in just a day or a little more,” said Mulligan.

Participants were tested for COVID-19 only if they developed symptoms, leaving unanswered whether vaccinated people could get infected but show no symptoms and unknowingly spread the virus.

FDA has told companies they must track half their participants for side effects for at least two months, the time period when problems typically crop up. Pfizer expects to reach that milestone later this month, but said Monday no serious safety concerns have been reported.

Because the pandemic is still raging, manufacturers hope to seek permission from governments around the world for emergency use of their vaccines while additional testing continues — allowing them to get to market faster than normal but raising concerns about how much scientists will know about the shots.

The FDA's scientific advisers last month said they worry that allowing emergency use of a COVID-19 vaccine could damage confidence in the shots and make it harder to ever find out how well they really work. Those advisers said it's critical these massive studies are allowed to run to completion.