Ok, so we’re supposed to accept this guy’s ‘scientific’ analysis, even though it contains very few references to primary research or source material (and even then, only ones which support his claims), nor any statistical analysis to show things like confidence intervals in his calculations (although I get the impression he has 100% confidence in himself)?
He criticises the academics on SAGE but then produces a paper in response that has zero academic rigour to it. Most of his assertions appear to be based on statements such as “everybody knows that...” rather than pointing to an actual study or piece of research that backs up any of his claims. He dismisses mathematical modellers on the basis that he had a chat to some once and wasn’t impressed!
On to his central assertions. Yeadon claims that SAGE are wrong to assume that the population has little pre-existing immunity to Covid. This is on the basis that “everybody knows” that there is no such thing as a novel virus and that, for Covid, exposure to viruses such as SARS, MERS and even the common cold will give humans some form of immunity.
Now, for SARS and MERS I can see some logic to that argument, as Covid is a SARS type virus. It may help partly explain why Far East countries appear to be fairing better than Europe or the Americas.
However, to the best of my knowledge, I’m not aware that either of those diseases ever reached the UK. Even if a few people who had been to Asia or the Middle East during those epidemics did have some exposure to them, I doubt that the numbers in the UK would be particularly high (in fact, I think we can safely assume they’re very small).
That leaves us with the common cold argument. In fairness, he narrows this down to those colds caused by coronaviruses.
Yeadon states that it is his “belief” that previous exposure to these viruses will provide an immune response to Covid, but presents zero evidence to back up that claim. He also states that this view is shared by “multiple top quality research groups around the world”, but fails to reference any of them. He also fails to answer, or even consider, the obvious question - if having had the common cold provides some level of immunity to Covid, then how come it doesn’t even provide immunity to the common cold?
His second assertion is that the reliance on antibody testing has under-estimated the number of people in the UK who have been exposed to Covid already. This is estimated by SAGE to be around 7% of the population based on serology results, leaving the other 93% vulnerable to the virus.
Yeadon disagrees with this estimate, preferring to use the infection fatality rate (IFR) of the disease to work back from the number who have died and calculate the total number of the population who have therefore been exposed (surely this is a form of mathematical modelling?). Anyway, many of you will be aware that the IFR for Covid is a controversial subject, with a great many estimates from primary research which cover an extensive range of possibilities.
Yeadon, however, has no problem in identifying the ‘correct’ answer, as he chooses to use the calculation by John Ioannadis (who he describes as “the person who is pre-eminent in this field”), without the need to bother himself with any of the other possibilities. Now, words I’ve heard to describe John Ioannidis include ‘controversial’ and ‘maverick’, but I’ve never heard him described as pre-eminent before.
Of course, the IFR calculated by Ioannidis (0.2%) just happens to be the smallest out of the range of possibilities from studies across the globe. The World Health Organisation estimates the IFR to be in the range 0.5-1.0%, whilst the most recent systemic review of IFR studies concludes it is 0.68%.
Using the 0.2% figure, Yeadon estimates that 28% of the UK population has already been exposed to Covid and is therefore immune. The epidemic, he therefore claims, is over. Hurrah!
Had he used the 0.5, 0.68 or 1.0% estimates for IFR, the proportion of the UK population exposed would be 11.2%, 8.2% or 5.6% respectively. Note that the 0.68% IFR estimate results in a level of exposure similar to that suggested by SAGE. However, we obviously need not concern ourselves with this, as Yeadon doesn’t even bother mentioning them as possibilities.
Finally, of course, there is his claim that, if 28% of the population has already been exposed to Covid, it necessarily follows that the epidemic is over. He provides no evidence or academic references to back up this assertion, despite it falling considerably short of the 60-70% figure often quoted to obtain herd immunity. He also fails to consider whether exposure necessarily leads to immunity and/or whether such immunity might be transient.
Other than that, a solid piece of work that adds greatly to our knowledge of this virus!
