German company BioNTech and its US partner Pfizer announced on Monday that early results from ongoing Phase III trials showed that their vaccine was 90% effective in preventing COVID-19 infections.

The statement from the two companies is the first release of successful data from a large-scale trial of coronavirus vaccines.

According to their reports, they found no serious safety concern connected with the vaccine. Researchers believe the immunizing effects will not be short-lived.

Read more: COVID-19 vaccine update: Who are the front-runners?

If substantiated, the Pfizer and BioNTech vaccine would be a breakthrough in the fight against the coronavirus pandemic.

Effects could last 'at least a year'

BioNTech's CEO Ugur Sahin told Reuters that: "We should be more optimistic that the immunization effect can last for at least a year."

"The first set of results from our Phase III COVID-19 vaccine trial provides the initial evidence of our vaccine's ability to prevent COVID-19," Pfizer chairman and CEO Albert Bourla said in a statement. 

Analysis of the experimental vaccine trials appeared to effectively prevent infection in participants "without prior evidence of SARS-CoV-2 infection," the joint statement said.

Pfizer cautioned that the initial protection rate may still change as time goes on and made clear that the vaccine was unlikely to be available before the end of the year. Nevertheless, Pfizer's senior vice president of clinical development, Dr. Bill Gruber told the Associated Press: "We are very encouraged."

Read more: Germany warns against COVID 'vaccine nationalism'

Biden and Trump welcome vaccine news

US President-elect Joe Biden welcomed the promising results from the vaccine trials, but warned that widespread vaccination was still months away. He also urged the US public to continue wearing masks and social distancing. 

"Today's news is great news, but it doesn't change that fact," Biden said in a statement. "Today's announcement promises the chance to change that next year, but the tasks before us now remain the same."

US President Donald Trump, celebrated the news and the boost to the stock market as "SUCH GREAT NEWS," in a post on Twitter.

European stock markets reacted positively to the news with Pfizer's share increasing 6% while BioNTech's US stocks rocketed up by 18%.

EU waiting for more data before approval

German Health Minister Jens Spahn said the European Union will wait to approve the vaccine until late-stage safety data is collected to ensure the broadest possible acceptance for the vaccine.

"Most important for acceptance is that we make clear from the beginning that we will wait for clinical trials in Phase III before approval," he said.

Spahn welcomed the promising progress on a coronavirus vaccine, but added that the German government doesn't want to make any hasty promises and bring something too quickly on the market.

A possible coronavirus vaccine could be ready to go in the first three months of 2021, he said.

Read more: Coronavirus: The race to save Germany

Science community reacts with optimism

William Schaffner, infectious diseases expert at Vanderbilt University Medical Center in Nashville, Tennessee responded to the published data, saying: "The efficacy data are really impressive. This is better than most of us anticipated. I would have been delighted with efficacy of 70% or 75%. 90% is very impressive for any vaccine. The study isn't completed yet, but nonetheless the data look very solid."

Bernd Salzberger, head of Infectiology at the University Hospital Regensburg in Germany said: "Although only a few events — a total of 94 cases - have been observed in the study so far, this is a very good result. No serious side effects have been reported — overall a very positive result, which will probably lead to an early approval."

Marylyn Addo, head of tropical medicine at the University Medical Center Eppendorf in Hamburg, Germany was more cautious, saying: "Primary data are not yet available and a peer-reviewed publication is still pending. We still have to wait for the exact data before we can make a final assessment."

Vaccine already in production

Over 43,500 people took part in the trial which has been ongoing since late July. The two companies said they would apply for authorization with the US Food and Drug Administration in the coming week.

Pfizer and BioNTech already have a $1.95 billion (€1.64 billion euros) contract to deliver 100 million vaccine doses to the USA. They also have agreements with the EU, UK, Canada and Japan.

Production of the vaccine has already begun in order to save time. They expect to globally produce up to 50 million doses by the end of 2020.

Up to 1.3 billion doses are expected to be produced in 2021, Pfizer said.

The reported 90% effectiveness is well above the 50% effectiveness that the US Food and Drug Administration requires in order to authorize a coronavirus vaccine.

Vaccine testing doesn't end at Phase 3

While the speed at which these vaccines are progressing is unrivaled in humanity's vaccinology history, experts warn we still have a long way to go to achieve a safe and effective vaccine.

Although clinical trials can show that a vaccine is safe and effective among tens of thousands and even hundreds of thousands of people, it's not possible for these trials to encapsulate every possible side effect that could occur among certain people or after an extended period of time.

That's why, even after a vaccine has been rolled out, it's critical to monitor the safety and efficacy of vaccines, said Naor Bar Zeev, deputy director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health in the US.

"There is never certainty," Bar Zeev told DW last month. This ongoing surveillance is sometimes referred to as "Phase 4" in clinical trials — and it can take many years.

rs, ab/rt (dpa, Reuters, AP)