Building on some of the figures above and looking forward to herd immunity kicking in.
If we take 73% as the percentage of the population which need to be immune before that's achieved. With a UK population of 62M that's 45M
A reasonably supported estimate is that 20% of the population have 'had' COVID-19, a good proportion asymptomatic and/or not tested (12M).
Since there will be overlap (ie people who've been infected, knowingly or not, who then get vaccinated and another element who had been infected but whose antibodies have dropped below protective level) of, say, 4M, once we've vaccinated 37M (first or both doses), we'll be over the 73%. (NB 5+M fewer if we exclude the 8M under 10s from the calculation.)
From one of my posts above, if the UK programme continues on plan, we should have 32M vaccinated by end April (assumes 400,000 a day from 6 March split half and half (1st/2nd dose)).
So 10 May to hit 37M and expectations of (effective) herd immunity. (NB 15 days quicker if we exclude the 8M under-10s from the calculation.)
Caveats: Depends on
= vaccination programme continues at pace (300,000 daily rising to 400,000 by 6 Mar, and maintained, 7-day averages)
= how effective the vaccine is (we hope 90-95%)
= how infectious the viral strain is (come May) - factors into 'R' and NB it's going to be a lovely May (well last year it was
)
= restriction measures reducing R - these measures will have been progressively revised across the UK by then
assumes vaccines stop person transmitting (as well as getting infected with symptoms).
Copied from my previous post: