People are 'likely' to need a third dose of Covid-19 vaccine according to Pfizer boss, Albert Bouria.
The Pfizer CEO said another jab could be necessary after the second one - and every year thereafter.
He told a panel discussion that a booster shot should probably be administered six to 12 months after the second dose.
He also said people are likely to need to be immunised against coronavirus annually.
Speaking on the next step in the vaccination programme to CNBC, Dr Bourla said: "A likely scenario is that there will be likely a need for a third dose, somewhere between six and 12 months and then from there, there will be an annual re-vaccination, but all of that needs to be confirmed."
He added that variants "will play a key role" in how regularly people will need to have their covid immunity topped up.
Dr Bourla explained the covid vaccine will be in the same category as the flu jab that is updated and re-administered year on year.
He said: “There are vaccines that are like polio that one dose is enough...and there are more vaccines like flu than you need every year.
"The Covid virus looks more like the influenza virus than the polio virus."
Last month, UK Health Secretary Matt Hancock says he can see an "end" to the pandemic, with coronavirus managed "more like flu" with repeated and updated vaccinations.
In response to a question about the end of the pandemic, he said: "It depends what you mean by 'end'. I see an end where Covid is managed more like flu: we repeatedly vaccinate, we update the vaccines according to mutations and we manage the challenges, especially around transmissions over winter.
"I'm confident that's where we can get to. I want to get to a position where we can have an updated vaccine in weeks or months, not a year."
A booster shot is aimed at protecting against future variants, which may be better at evading antibodies from vaccine than earlier strains of the virus.
