Herd immunity was never UK policy, Chris Whitty tells Covid inquiry

Herd immunity was never government policy during the Covid pandemic and it was a major communications failure that some people early in the pandemic believed it was, Prof Sir Chris Whitty told the Covid inquiry.

Giving evidence, Whitty, the chief medical officer for England, said opting for herd immunity was “inconceivable” and would have caused “an extraordinarily high loss of life” without necessarily achieving its goal.

Whitty said that in about March 2020 he tried to stop ministers and others publicly discussing the idea, given the concept was complex and nuanced: “Frankly, there was a lot of chatter by people who, at best, half understood the issues.”

Herd immunity was commonly understood at the time to mean allowing the virus to be transmitted unchecked through the population, with enough people catching it and gaining subsequent immunity that at some point infection rates would slow.

Arguing that no one in government was endorsing the idea, Whitty said the problem was ministers were discussing it as a possible natural course of the pandemic because of “a mashed-up understanding of some papers based on modelling that was not advocating it as a goal”.

Whitty said: “I don’t think I ever saw anybody on the record, or anybody sensible, aiming for it as a goal. I think some people tried to explain it as, ‘This is what would happen over time’, I think, frankly, unhelpfully.

“I think if we were to go back in terms of our communication errors along the way, and there were a lot, this is firmly one of the ones where I think we didn’t help the public by having a debate that I think, quite rightly, upset and confused a lot of people.”

Whitty did not identify who he believed had been unhelpful in discussing the idea, but the then prime minister Boris Johnson was among those who did so at the time.

Whitty said he sent WhatsApps to a group including Johnson, Matt Hancock, the then health secretary, and officials urging them not to talk publicly about herd immunity given its complexities and the likelihood of being misunderstood.

The idea of herd immunity – also used as a modelling term to look at the impact of various waves of a virus – as a way to eliminate Covid rapidly was nonsensical, Whitty said. He said that even after the highly damaging first wave of Covid only about 20% of people had been infected.

Using herd immunity as a policy was also predicated on post-infection immunity being permanent, which it was not for Covid, Whitty said, and also on the doubtful practicality and morality of asking older and clinically vulnerable people to isolate for long periods.

Asked about scientists and others who supported the plan in the so-called Great Barrington declaration, Whitty said: “I think they were just wrong, straightforwardly. I thought it was flawed at multiple levels.”

However, he said, some people in government picked up the idea from modelling and “ran with it in a somewhat confused way”, and some discussed it as an idea “without having thought it through”.

He said: “It was clearly a ridiculous goal of policy, and a dangerous one, and lots of what was said [about it] could have led to considerable confusion, and did.”