As of mid-October, the World Health Organization (WHO) has identified 42 "candidate vaccines" at the stage of clinical trials, up from 11 in mid-June.
Based on supply projections, the companies said they expect to supply up to 50 million vaccine doses globally in 2020, and up to 1.3 billion doses in 2021.
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.
Dr Albert Bourla, the Pfizer chairman and chief executive, said that,"today is a great day for science and humanity".
Pfizer Inc and BioNTech'sCOVID-19 vaccine candidate was shown to be over 90 percent effective in preventing infection from SARS-CoV-2 in participants without prior evidence of novel coronavirus infection in the first interim efficacy analysis.
Pfizer just released incredible data - preliminary though it is - showing they've developed a vaccine that is MORE THAN 90% EFFECTIVE IN PREVENTING CORONAVIRUS INFECTIONS.
About 12 Covid-19 vaccines around the world are now in the final stages of testing, but Pfizer's is the first to report any results. BioNTech's shares soared 25% at intraday highs.
Along with the efficacy data generated from the clinical trial, Pfizer and BioNTech are working to prepare the necessary safety and manufacturing data to submit to the FDA to demonstrate the safety and quality of the vaccine product produced.
The efficacy rate is well above the 50% effectiveness required by the US Food and Drug Administration for a coronavirus vaccine. Pfizer's vaccine requires two shots, which need to be taken 28 days apart.
The data have yet to be peer-reviewed or published in a medical journal.
The trial, the company said, will continue until there has been at least 164 confirmed cases.
The U.S. COVID-19 death toll stands at over 237,000, with more than 9.9 million cases now reported in the country since the outbreak began, according to a Reuters tally.
USA biotech firm Moderna, several state-run Chinese labs, and a European project led by the University of Oxford and AstraZeneca are also thought to be closing in on potentially viable vaccines. The data will be discussed with regulatory authorities worldwide.
Vaccines are seen as essential tools to help end the health crisis that has shuttered businesses and left millions out of work.
While promising, this analysis alone does not provide enough information about the vaccine for Pfizer to ask the FDA for permission to distribute it.