Pfizer initially turned down the offer of developing a coronavirus vaccine because the company's top executives thought the virus would be rapidly contained, like Sars and Mers.
Dr Ugur Sahin and his wife Dr Özlem Türeci, the founders of BioNTech, were told, "Guys, this is not going to work", by the pharmaceutical giant as the virus was starting to sweep the globe in January 2020.
The mRNA technology, which has proved so crucial to the vaccine breakthroughs, was, at the time, also considered too experimental by Pfizer's vice president and chief scientific officer for viral vaccines, Dr Phil Dormitzer.
"My working assumption was that it [Covid-19] would be controlled", Dr Dormitzer admitted.
The rejection, revealed in a new book, came just days after the Turkish-born couple decided to dedicate BionNTech to creating an mRNA-based Covid jab, effectively gambling their business on something that had never been done before. Their company is now capitalised at $119.4 billion. Yet Dr Sahin and Dr Türeci remain close to Pfizer - and to Dr Dormitzer, or "Phil" as they know him.
Dr Sahin had a detailed image in his mind of how the pandemic would unfold but also thought the Pfizer man's assessment was "completely rational".
"After the phone call with Phil, I just thought for a second and said, 'we will call him again in a few weeks,"' Dr Sahin told The Sunday Telegraph.
The couple thought it only a "matter of time" before the drugs giant changed its mind - and they were right: a deal was announced between the two companies only a month later. Next week the Government is expected to announce a "booster" campaign for higher risk groups, with the Pfizer jab expected to be at the forefront of the programme. UK Prime Minister Boris Johnson will also announce the repeal of a series of measures from the Coronavirus Act which are now deemed unnecessary.
These include the powers to close-down sectors of the economy, such as business premises, or apply restrictions to events and gatherings.