Only a tiny proportion of the global population – maybe as few as 2% or 3% – appear to have antibodies in the blood showing they have been infected with Covid-19, according to the World Health Organization, a finding that bodes ill for hopes that herd immunity will ease the exit from lockdown.
“Easing restrictions is not the end of the epidemic in any country,” said WHO director-general Dr Tedros Adhanom Ghebreyesus at a media briefing in Geneva on Monday. “So-called lockdowns can help to take the heat out of a country’s epidemic.”
“Early data suggests that a relatively small percentage of the populations may have been infected,” Tedros said. “Not more than 2%-3%.”
Analysis of UK situation based on this data
UK Population = 67,800,000
WHO data – 2% infected = 2% x 67.8 million = 1,356,000 infected cases of Covid-19
WHO data – 3% infected = 3% x 67.8 million = 2,034,000 infected cases of Covid-19
Total number of Hospital deaths in UK = 17,337 (21st April 2020)
Based on infection rate @ 2% infected : 17,337 / 1,356,000 = 1.28 % Death rate
Based on infection rate @ 3% infected : 17,337 / 2,034,000 = 0.85% Death rate
Total reported cases in UK @ 21st April 2020 is 129,044 , so there is a huge disparity between this figure and the 1.356 million (2% Covid-19 infected) and 2.034 million (3% Covid-19 infected) of the UK population infected by Covid-19.
The calculations exclude deaths in the Community. Numbers reported today for the period ending 10th April, are too complicated for me to extrapolate.
Even so, extrapolating the numbers of Covid-19 infected in the UK according to the WHO infection rate of 2-3% shows that significant numbers have been infected, rather than the reported figure of 129,044 cases.
According to data from the best-studied countries such as South Korea, Iceland, Germany and Denmark, the overall lethality of Covid19 is between 0.1% and 0.4% and thus up to twenty times lower than initially assumed by the WHO.
Applying these figures to the UK data (17,337 deaths @ 21st April 2020) would yield figures of 4.33 million (0.4%) to 17.34 million (0.1%). These numbers appear to be much too high, and the 0.1% would see the UK well on the way to herd immunity.
These disparities indicate the need for more testing on a massive scale – Test ! Test ! Test ! according the WHO. However, the testing strategy needs to be more sophisticated and focused. In order to break the chain of transmission, there needs to be a clear Testing Strategy , with the aim of Test, Trace every positive result’s contacts (up to 100) , and Isolate every contact for 14 days.
Applying this strategy to the 4.301 new Covid-19 cases today (21st April) would involve a testing a total of 430,001 cases today – and do this each and every day. We are nowhere near that position !!
Source Dr Devi Sridhar , Professor of Global Health , University of Edinburgh – BBC Breakfast 20 April news clip.