Sunetra Gupta is Professor of Theoretical Epidemiology at Oxford University and one of the three primary authors of the Great Barrington Declaration, which argued against lockdowns and in favour of what she calls "focused protection."

March: "Coronavirus may have infected half of UK population"

In March 2020, she was the co-author of a paper that suggested that up to 68% of the UK's population may have already been infected asymptomatically by Covid-19 by 19th March 2020.

All the available evidence indicates that this cannot have been correct: the most recent ONS serological survey at the time of writing, in November 2020, estimated that by then 8.7% of the UK population would have tested positive for Covid antibodies (indicating a prior infection), and this is eight months later than Gupta's original claim, and after two waves of Covid and (at that time) over 60,000 deaths from Covid.

Gupta's paper was criticised immediately by British and Italian epidemiologists. To arrive at its conclusions, it assumed that only between one in 1000 and 1 in 100 infections would be at risk of severe disease, and of them only about 14% would die. In reality, in the U.K. at least 2 in 100 people require hospitalisation (a far stricter test than “severe disease”), of whom about 25% have died.

At the time the paper was released, more than 1 in 1000 people in Lombardy had been hospitalised already for Covid, which even if the entire population of Lombardy had already had Covid would have meant that this assumption was wrong. In some towns in Lombardy far more than 1 in 1000 people had already been hospitalised.

By early April, it was clear the severity estimates used were not correct. By April 4th, excess death data for Bergamo Province in Lombardy were running at 0.4% of the overall population. Even based on test results, by 2nd April, 5 in 1000 people in Lombardy had tested positive, half of whom were severe cases, and of whom 12% had died.

Later in April the serology studies which Gupta had called for in her paper started to come out, including in Geneva. However, not only were infection rates much lower than her work would have implied (only 5% in Geneva), they also gave IFRs that at 0.6% were far higher than the top of her range.

May: "I think [the Infection Fatality Rate] would be definitely less than 1 in 1000 and probably closer to 1 in 10,000"

Despite this mounting evidence, in May Gupta gave an interview claiming that “Covid is on the way out”:

I think that the epidemic has largely come and is on its way out in this country so I think [the Infection Fatality Rate] would be definitely less than 1 in 1000 and probably closer to 1 in 10,000. That would be somewhere between 0.1% and 0.01%. (May 2020)

By this point, 36,000 had died of Covid in the UK. If 100% of the UK’s population had had Covid by then, the UK would have had to have a population of 360 million people for her low-end IFR estimate to be right. (She did, after being challenged by the interviewer, then change this to 0.05%. This would mean a population of 120 million at a herd immunity level of 60%, which Gupta actually claims may be much higher than the true level.)

Since then Gupta has continued to claim that the UK may already have herd immunity:

"You can see why the seroprevalence level might be low, and you can also infer that the level of herd immunity needed to stop the thing from exploding again is actually much lower than the figures that are currently being thrown around quite incautiously might suggest. (July 2020)

She has also criticised New Zealand for eliminating Covid domestically:

"It seems to be very short-sighted, how can it possibly keep the virus out?

"I think the smugness, the self-congratulation with which it’s presented is misplaced. The self-righteous attitude is completely ridiculous. If it turns out that the rest of the world, through herd immunity or vaccination, manages to reduce the risk of infection, then what New Zealand will have done would be tantamount to not vaccinating your own child. Just waiting for everyone else to vaccinate their children and then go “ok it’s all safe now”." (July 2020)

At the time of her widely-publicised March paper, Gupta called for large-scale serological surveys to establish the real spread of the disease. She has since argued a different position – that sereological surveys offer an incomplete picture of the spread:

“Now we don’t know how exactly many people are at the moment immune or not available for infection, because we thought we’d be able to find this out by doing these antibody tests, but as it turns out the situation is a bit more complicated than that. So the seropositivity in other words how many people have antibodies is not a very good indication of how many people are immune.” (October 2020)

As a result of her changed view on serological surveys, Gupta has argued that herd immunity levels may have already have been reached:

"There is also the possibility, as we suggested in March, that a large swathe of the population has been exposed. Some have become immune, and therefore exhibit antibodies, or don’t because those antibodies have decayed. And some were resistant to start with. Under those circumstances, no, we shouldn’t see a huge surge in infections in those regions like London and New York where we’ve had a major incidence of infection and death." (July 2020)

September: "From what we've seen happening in London ... around 15 to 20 percent could give us some degree of resistance"

Despite insistences that her high estimates of potential levels of immunity are simply illustrating the range of possibilities, Gupta has also said outright that she believes very low levels of serological spread are likely to provide herd immunity:

*Allison Pearson: "If you were going to make a very educated guess, as you’re one of the few people in the world who could, where would you put [the level of resistance to infection]? We’re seeing a higher number of cases now but still comparatively low deaths aren’t we?"*

Sunetra Gupta: "The real issue is what level of antibody positivity gives you sufficient resistance in the population to keep the risks of the virus as low as possible. And from what we’ve seen happening in London, in New York, in Stockholm, over the summer, I would imagine that around 15 to 20 percent could give us some degree of resistance, significant resistance to the further growth of this virus."

Allison Pearson: "And we might be closer to that than we know."

Sunetra Gupta: "That’s exactly correct." (September 2020)

Since that interview, London has had one of the worst Covid second waves, with its prior outbreak apparently providing little or no benefit in terms of reduced spread.

In an interview with The Times in October, Gupta said that her anti-lockdown strategy would bring the death rate to a stable level by Christmas, and that a death rate that rose above that of flu would be a time to rethink such a plan:

“We would have flu as our benchmark. We’d say, ‘What’s going on with flu?’ If it starts to edge above flu then we start to think a bit more carefully about what else we can do, but up to that point shielding the vulnerable as best we can is probably overall going to cause fewer deaths and less stress. That’s the message really.” (October 2020)

At the time of writing (January 2021), deaths have vastly outstripped any flu epidemic, though Gupta has not suggested that this warrants any change in strategy. On January 5th, 2021, Gupta appeared on the Today Programme, arguing that the UK would have had herd immunity already if not for lockdowns, because so many people would have already been infected by the virus.

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