The two companies earlier on Monday became the first drugmakers to release successful trial data, saying their vaccine was shown to be more than 90% effective, a major victory in the fight against the pandemic.

“We should be more optimistic that the immunisation effect can last for at least a year,” CEO Ugur Sahin told Reuters.

While it was not yet known how long the protection would last, research on recovered patients and earlier findings on their vaccine led him to believe protection would not be short-lived.