The CEO of Pfizer is expressing confidence in the company's coronavirus vaccine candidate, which he says could potentially receive approval from the FDA this October.

Pfizer CEO Albert Bourla spoke with Time this week after the pharmaceutical company recently released the first clinical data on its COVID-19 candidate, which showed it generated neutralizing antibodies at levels 1.8 to 2.8-times the levels found in patients who recovered from COVID-19. There were, however, some side effects including fevers.

"What we learned is that this vaccine can neutralize the virus," Bourla told Time. "...For me, it was the moment when I saw the data, plus many other data that we haven't published yet, [that] made me say that until now I was thinking if we have a vaccine. Now I'm discussing when we're going to have a vaccine."

Bourla added that "we have a lot of indications that make me feel that really it should make it," noting that it won't be until "we have the final study" that it's clear whether the vaccine candidate works but saying that this answer should come around September.

"So for a potential approval in October, if we are lucky," he said. "It's feasible."

If that happens, Bourla says "we will have already manufactured doses that will be readily available" as soon as the FDA approval comes. In announcing its recent data, Pfizer said it's looking to "manufacture up to 100 million doses by the end of 2020 and potentially more than 1.2 billion doses by the end of 2021."