Chris Whitty has blasted anti-vaxxers who "should be ashamed" after pop star Nicki Minaj tweeted an evidence-free "myth" about the Covid jab.

England's Chief Medical Officer hit out after Minaj, who has more than 150million Instagram and 22million Twitter followers, claimed "my cousin in Trinidad won't get the vaccine cuz his friend got it & became impotent."

In a powerful response, Prof Whitty told a No10 press conference: “There are a number of myths that fly around, some of which are just clearly ridiculous, some of which are clearly designed just to scare.

"That happens to be one of them - that is untrue.

“My own strong suggestion, if I may, to the media present is repeating them in public actually just gives them credence which they don’t need. They’re untrue, full stop.

“If you think about where we are actually overall…. the great majority of people are getting vaccination. The great majority of people are ignoring these myths.”

Prof Whitty said many people who are vaccine hesitant are exercising their right to choose, and may have wider concerns.

But he added: “There are also people who go around trying to discourage other people from taking a vaccine which could be lifesaving or prevent them from having life changing injuries to themselves.

“Many of those people I regret to say, I think know they are peddling untruths but they still do it.

"In my view, they should be ashamed.”

Boris Johnson also waded into the row, saying: "I'm not as familiar with the works of Nicki Minaj as I probably should be, but I'm familiar with Nikki Kanani, superstar GP of Bexley who has appeared many times before you, who will tell you that vaccines are wonderful and everybody should get them.

"So I prefer to listen to Nikki Kanani."

In a bizarre twist, Minaj then replied to Prof Whitty's comments on Twitter, saying: "I love him even tho I guess this was a diss? The accent ugh! Yassss boo!!!"

She also posted a voice note directed at Mr Johnson, saying: "Send this to the prime minister & let him know they lied on me. I forgive him. No one else. Only him."

In the recording, Minaj puts on an English accent and claims to have gone to school with Margaret Thatcher and attended Oxford University.

She offered no evidence for these claims.

It came after Prof Whitty showed stark charts at the press conference demonstrating the difference achieved by the vaccine.

A 30-year-old with no vaccine has around the same risk of being hospitalised as a 70-year-old with both doses, he said.

But he also showed charts warning the case, death and hospitalisation rates are all far higher now than they were on this date in 2020.

Despite the protection of the vaccine, “it wouldn’t take many doubling times to get into trouble”, he warned - with nearly 150 deaths a day.

He added: “I don’t think you need a medical degree to know Autumn and Winter are when respiratory viruses are hugely advantaged.”

Chief Scientific Advisor Patrick Vallance added: “If you tried to do this six months ago, the number of deaths and hospitalisations would be through the roof.”

Meanwhile the Prime Minister warned he could bring in vaccine passports at short notice.

“It’s just not sensible to rule out completely this kind of option now when we must face the fact that it might still make the difference between keeping businesses open at full capacity or not,” he said.

Boris Johnson also promised the new version of the travel traffic light system of countries - set to be changed by October 1 - will be unveiled “shortly”.

He said: “We’ll be saying a lot more shortly about the traffic light system, about simplifying it and what we can do to make the burdens of testing less onerous for those coming back into the country.”