Quote Originally Posted by Muddy Retriever View Post
A study carried out by Public Health England and Cambridge University calculates a much larger proportion for the UK.

https://www.telegraph.co.uk/news/202...g-north-south/

The new data also suggests that huge numbers of people have already been infected with the disease, around 6.5 million overall in England, including 1.8 million in London.

Overall, around one in 5 Londoners has been infected by the virus since the epidemic began, compared with 14 per cent of people in the North West, 11 per cent in the Midlands, the North East and Yorkshire, 10 per cent in the East of England and eight per cent in the south east.

This study is the same one that thinks there is only 24 new daily infections in London at the moment - as WP has mentioned. If true, could this be that an element of herd immunity kicking in? The number who have had the virus may be more than estimated above. The conventional wisdom is that 60% infection is required to achieve herd immunity. However, the Liverpool School of Tropical Medicine thinks it is much less than that because it is based on the assumption that we are all equally susceptible to the disease. Clearly that is not the case. They say that gradually the pool of easily-infected individuals dries up and the virus has to search out new victims who are less-easily infected.
So a bit more than 10% have had it, if they are correct.
R varies with the organism, and with behaviour - in tight lockdowns it will be lower, with normal freedoms, higher.
And a low, or even zero R does not mean nobody is susceptible, it just means nobody is getting it, because of a
tight lockdown, for example.
The % of the population needed for herd immunity varies with R - and is 90% for an R of 10, 50% for an R of 2.
The results of more widespread serological testing will be interesting.