UK vaccine chief Kate Bingham will step down at the end of the year.
Her exit from the top job comes amid growing concerns over her conduct while in the position.
Over the weekend, it emerged her taskforce spent £670,000 on PR consultants in a decision that was not signed off by ministers.
According to documents leaked to Sunday Times, the taskforce has used eight full-time PR consultants from a London-based firm to oversee Ms Bingham's media strategy since June.
It means each consultant earned more than the prime minister’s salary with a pay-out worth the equivalent of £167,000 per year.
Ms Bingham, 55, a venture capitalist who is married to junior Tory finance minister Jesse Norman, was also forced to deny claims she shared commercially sensitive information about the vaccine with investors.
Downing Street continues to insist that Prime Minister Boris Johnson has full confidence in Ms Bingham.
Reports suggested Ms Bingham’s contract ran to the end of the year and she was always expected to leave at that point.
However, Labour leader Sir Keir Starmer said the vaccine tsar’s £670,000 PR bill “can’t be justified”.
He told London’s LBC Radio on Monday: “You cannot justify that sort of money being spent.
"If only it was the only example.
"There are lots of examples of lucrative contracts going without any due process and I think the public mood on this is very, very clear."
Ms Bingham has previously denied revealing potentially sensitive information to investors.
She told MPs she divulged “nothing commercially sensitive, nothing confidential”.