Pfizer and BioNTech's coronavirus vaccine may be the first candidate to be available in the market after the companies on Friday formally asked the US Food and Drug Administration (FDA) to allow emergency use of the new drug.

"It is with great pride and joy, and even a little relief, that I can say that our request for emergency use authorization for our COVID-19 vaccine is now in the FDA's hands," said Pfizer chief executive Albert Bourla.

He referred to it as "a historic day for science and for all of us."

Read more: When will we have a COVID-19 vaccine?

Days earlier, the American pharmaceutical giant and its German partner BioNTech had announced that their COVID-19 vaccine appeared to be 95% effective at preventing mild to severe COVID-19 infections. The latest results came at the conclusion of phase-three testing of the vaccine.

"The FDA recognizes that transparency and dialogue are critical for the public to have confidence in COVID-19 vaccines," the organization's head Stephen Hahn said in a statement. "I want to assure the American people that the FDA's process and evaluation of the data for a potential COVID-19 vaccine will be as open and transparent as possible."

While it remains unclear how long the FDA will take to study vaccine data and provide necessary approvals, it could be available as early as the first half of December. 

"The companies will be ready to distribute the vaccine candidate within hours after authorization," the companies’ statement said.

However, the initial supply of the vaccine will be rationed. The companies estimate that 50 million doses could be made available by the end of 2020, with 25 million available for use in the US next month. In addition to that, 30 million doses may be available in January and 35 million more in the next two months.

Notably, emergency approval doesn’t mean that the vaccine has received full approval. It is deemed investigational until all authorities sign off on it.

Read more: Can we trust recent COVID vaccine successes?

Each recipient will need two shots in a period of three weeks. There have also been some concerns about the logistical practicality of the vaccine, which must be stored at  -70 degrees Celsius (-94 degrees Fahrenheit)

As other vaccine competitors like Moderna Inc and AstraZenecaalso make significant progress, Pfizer and BioNTech said they had started "rolling" applications in Europe and the UK.

Since the start of the pandemic, COVID-19 has killed nearly 1.4 million people and infected over 57 million.

see/sms (AP, AFP, dpa)