He said data from around five weeks ago suggested “something like a 10 per cent antibody positivity in London”, with three to four per cent antibody positivity in other regions and even less in some areas.
At the current time, he said he would “not expect to see antibody levels much above mid-teens” in any region.
Sir Patrick said that while the ‘R’ number – the number of people infected by somebody with coronavirus – is below one across the country, prevalence of infection will be different depending on region.
He said: “We know that cities and densely-populated places have a higher prevalence than rural places… and an option that could be considered is to think about whether measures could be done locally versus nationally.”
But that could lead to difficulties such as whether people could use public transport to travel, he said, adding: “Once you go to a regional approach, you effectively are saying that you are going to demarcate regions very carefully and you’ve got to control the flow between regions. But that is a possibility.”
On immunity, Sir Patrick said evidence from around the world suggests the vast majority of people who have had the infection have “some form of antibody response” and get “some degree of protection”.
But he said the exact amount of immunity people developed is not known, adding that they “almost certainly” will not have absolute immunity.