Pfizer CEO Albert Bourla has called his company's Covid-19 vaccine candidate "the greatest medical advance in the last 100 years.”
Pfizer announced earlier on Monday that the vaccine is more than 90% effective according to early data.
"Emotions are very high," Bourla told CNN Chief Medical Correspondent Dr. Sanjay Gupta.
You can imagine how I felt when I heard the results yesterday at 2 p.m. I think that likely, based on impact, this will be the greatest medical advance in the last 100 years. It is extraordinary, but it's coming at a time that the world needs it the most."
The drugmaker has no safety concerns so far, Bourla added.
"What we know right now -- it is with very, very high level of confidence these are very highly effective vaccines. What we know so far, it means that we don't have any safety concerns, but we need to wait until the results are there," he said.
He added that the vaccine will be available free to all American citizens.
The CEO said Pfizer planned to have more than 1 billion doses available globally next year.
Around 10 million doses of the vaccine are to be manufactured and made available to the United Kingdom by the end of 2020 if approved by regulators, a Downing Street spokesperson said Monday.
According to the spokesperson, the UK has procured 40 million doses of the Pfizer candidate vaccine in total.
Bourla did tell CNN that it was unclear how long protection from the vaccine could last.
How long this protection lasts is something we don't know," he said Monday.
When asked if the timing of the announcement was related to the US election, Bourla said: "The science brought it exactly at this time. We announced it the moment we learned about it, and I said multiple times the election for us is an artificial timeline."
US President-elect Joe Biden congratulated the scientists behind the vaccine in a statement Monday and thanked "the brilliant women and men who helped produce this breakthrough and to give us such cause for hope."
US President Donald Trump also reacted on Twitter, writing: "STOCK MARKET UP BIG, VACCINE COMING SOON. REPORT 90% EFFECTIVE. SUCH GREAT NEWS!"