The U.S. could have access to Pfizer’s coronavirus vaccine before the end of the year. Pfizer CEO Albert Bourla said on Sunday that the company would supply “hundreds of thousands of doses” of its coronavirus vaccine to the country as soon as regulators at the U.S. Food and Drug Administration (FDA) approve the shot by the end of October.

In an interview on the CBS show “Face the Nation,” Bourla revealed that the Pfizer coronavirus vaccine distribution would be contingent on the approval of the FDA. He also said Pfizer is prepared to distribute doses of the vaccine to the U.S. once the vaccine gets the approval of the regulatory body.

“I cannot say what the FDA will do,” said Bourla. “But I think it’s a likely scenario, and we are preparing for it,” he added.

Bourla said he’s “quite comfortable” that the coronavirus vaccine that Pfizer is developing with German drugmaker BioNTech SE is safe and effective and that it is likely the U.S. will deploy a COVID-19 vaccine to the public before 2021. In July, the U.S. government earmarked $1.95 billion for Pfizer and BioNTech to produce and deliver 100 million doses of their coronavirus vaccine to the U.S. once it has been proven safe and effective. The deal was part of Operation Warp Speed, Donald Trump’s initiative to speed up the development and production of COVID-19 vaccines and treatments.

Pfizer and BioNTech are among the frontrunners in the race to develop a coronavirus vaccine, alongside Moderna Inc. and AstraZeneca Plc. Bourla said Pfizer and BioNTech’s partnership has a 60 percent chance of knowing the efficacy of their experimental vaccine by October.

“Of course, that doesn’t mean that it works; that means that we’ll know if it works,” he said.

Pfizer and BioNTech have expanded the number of participants in their clinical trials to include more people with diverse backgrounds. On Saturday, Pfizer said in a statement that they would expand their target participants from 30,000 to 44,000 to include people as young as 16, as well as those with HIV and Hepatitis B and Hepatitis C.

As of Sunday, Pfizer had already invested $1.5 billion for the development of its coronavirus vaccine candidate. He admitted it would be financially painful for the company if the vaccine ends up not being safe and effective.

“At the end of the day, it’s only money,” said Bourla. “But that will not break the company, although it’s going to be painful,” he said.

Vaccine Discussion about the Cuba's life-saving lung cancer vaccine called CimaVax-EGF is growing rapidly. REUTERS/Eric Gaillard