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Sun 25 October 2020
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Nafeez Ahmed on a new report which shows the disastrous consequences of Donald Trump’s adoption of the false choices of fringe scientific theory

This week, the White House embraced the Great Barrington declaration calling for a herd immunity strategy that would allow COVID-19 to spread among healthy young people while shielding the elderly and vulnerable.

The huge decline in national health represented by a herd immunity scenario, even with shielding, will result in both a massive decline in national life expectancy, and a correlating collapse in GDP.

But the scientific evidence shows that the approach could not only lead to nearly 3 million American deaths but would create significant deaths among healthy young people while generating unprecedented economic shocks.


The John Snow Memorandum on the Great Barrington Declaration

On Wednesday, 80 top international public health experts, including senior epidemiologists infectious disease experts, and economists from Oxford, Cambridge, Harvard, the Federation of American Scientists, the Geneva Centre for Emerging Viral Diseases, and dozens of other leading institutions, signed a landmark statement published in The Lancet about the scientific consensus on the COVID-19 pandemic.

Their open letter, known as the John Snow Memorandum, warned that the White House’s new approach is based on a “dangerous fallacy unsupported by scientific evidence” that “would place an unacceptable burden on the economy”.

One of the signatories of the open letter – Dr. Gavin Yamey, Professor of Global Health and Public Policy, and Director of the Centre for Policy Impact in Global Health at Duke University – told me that in his estimate, between 1 and 2.5 million Americans would likely die from COVID-19 due to a herd immunity strategy.

Yamey bases his figure on widely available and undisputed data. The Centers for Disease Control places the COVID-19 infection fatality rate for the US at around 0.65 percent. Fatality rates vary depending on local conditions. So, for instance, if the healthcare system ends up getting overwhelmed and unable to treat people with severe symptoms, the death rate drives up, which is why at one point Arizona saw rates of 2.1 percent, and New York saw rates as high as 10 percent.

These figures suggest, fairly conservatively, that some 2.1 million people would be expected to die in the US if the virus is allowed to spread uncontrolled. And the evidence suggests that this would happen even with efforts to shield the most vulnerable.  


The Limits of ‘Shielding’

The Lancet open letter points out that shielding is essentially impossible: if the virus is allowed to spread widely among younger people, there will inevitably remain lines of transmission to the elderly and vulnerable that cannot be contained. Once transmission begins to spread to the latter groups, the logic of the virus reproduction number (with one person infected two or more people in an uncontrolled scenario) rapidly leads to exponential growth. That, for instance, is why 50,000 people still died in the UK even with an extended lockdown.

“Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population,” explains the letter. “Prolonged isolation of large swathes of the population is practically impossible and highly unethical. Empirical evidence from many countries shows that it is not feasible to restrict uncontrolled outbreaks to particular sections of society.”

Because immunity seems to wane after a few months, shielding would need to continue virtually indefinitely to keep the virus at bay. As there is “no evidence for lasting protective immunity to SARS-CoV-2 following natural infection,” the letter observes, “the endemic transmission that would be the consequence of waning immunity would present a risk to vulnerable populations for the indefinite future.”

The herd immunity strategy, then, does not offer a way out of the COVID-19 pandemic, but instead would “result in recurrent epidemics, as was the case with numerous infectious diseases before the advent of vaccination.”


False Opposites

The open letter is yet another development illustrating how the public discourse around COVID-19 has needlessly become increasingly polarised around extreme positions – pro-lockdown or anti-lockdown; save lives from COVID-19 or kill people by crushing the economy; stop deaths in the near-term or stop deaths in the long-term. Yet the new letter shows that this is a false dichotomy, noting that the goal of any strategy to defeat the virus will allow “life to return to near-normal”.

Indeed, the fundamental parameters of this debate are flawed, because they ignore some of the most robust and undisputed scientific facts around the impacts of COVID-19.

The argument of those who call for a herd immunity strategy is that the net impact of lockdowns is far worse than the COVID-19 pandemic itself. In particular, herd immunity proponents behind the Great Barrington Declaration have pointed to the disparity between the much higher COVID-19 fatality rates for people over 65, and the much lower fatality rates for young people. The import is that impacts on the wider population will be negligible, which is why a shielding strategy of older and more vulnerable people makes perfect sense.

But this argument relies on a bait and switch where herd immunity proponents avoid informing their readers and listeners of the specific probable impacts on the people expected to get infected to create herd immunity, and fail to explain how old people can actually be practically protected from getting the virus while everyone else gets the virus.

Even before we begin considering the broader impacts of uncontrolled transmission resulting in Yamey’s scenario of millions dead, it’s possible to develop reasonable estimates of the potential scale of death even for the supposedly safe age groups – and the numbers are sobering.


The Numbers to Achieve Herd Immunity

In England, the estimated fatality rate for 15-44-year-olds is around 0.03 per cent.

Now at first glance, this would suggest that for any given individual in that age range, a 0.03 per cent chance of death appears minuscule. This is a 1 in 3,333 chance of death. Which seems trivial until we use it to estimate the number of younger people that would therefore be likely to die.

When we apply this case fatality rate to the number of 15-44 year olds in the UK – approximately 25.2 million people – who would need to become infected with COVID-19 in a herd immunity strategy, then we would expect to see somewhere around 7,500 deaths as a result. 

In a scenario where 129 million Americans and 13 million Britons are infected with COVID-19, it will be impossible to contain the virus away from the old and vulnerable. 

Most scientists estimate that some 70 percent of a given population would need to acquire COVID-19 for herd immunity to work. But this is nowhere near 70 percent – it’s about 37 percent of the UK population. So we would need greater numbers of children below the age of 15, and adults between ages 44 and 65, to get the virus for the UK to secure herd immunity. This would rapidly lead to more dangerous lines of transmission and higher fatality rates, higher than 14,000 people.

What if the herd immunity threshold was lower? Some scientists have speculated using mathematical models that it could be around 50 percent, or 43 percent, or as low as 20 percent. None of those models have yet been backed up by real-world observations, but even if we assume that the lowest threshold is possible, we can use our estimate above to deduce a likely scale of death at the lowest speculated threshold.

Even if just 20 percent of the UK population acquired the virus to achieve the herd immunity goal through infection – in which case around 13.4 million people between the ages of 15 and 44 would need to get COVID-19 – at the miniscule case fatality rate of 0.03 percent for this age range, we would expect some 4,000 young adults to die.

So anywhere from 4,000 to 7,500 young adults could die in the UK from a deliberate herd immunity strategy – and more likely up to 15,000 younger people if the threshold is 70 percent, accounting for higher fatality rates as older ages are infected.

A similar calculation can be performed for the United States, where the CDC’s estimated fatality rate for 20-49-year-olds is around 0.02 per cent, which means roughly 1 in 5000 people in this age range who acquire COVID-19 would die. 

When we apply this case fatality rate to the number of 20-49 year olds in the US – approximately – 129 million people – if all of them were to get COVID-19, we would expect to see some 25,800 of these younger people to die. 

This is only about 39 per cent of the US population. So if herd immunity needs a threshold of 70 per cent of the population as most scientists believe, we would expect many more numbers to die from lower and slightly higher age ranges on a herd immunity trajectory. Once again, in this case we are looking at nearer to some 50,000 younger Americans dying at this threshold. 

If, however, the threshold is closer to the highly optimistic 20 percent range, some 65 million people, the death rate would still be significant even if all infected could be rigorously contained within the 20-49 year old age range: around 19,500 people in this age range would probably die.

So in the US, a herd immunity strategy that worked perfectly to shield the eldest and most vulnerable would still result in between 19,500 and 25,800 deaths at lower herd immunity thresholds, but more likely around 50,000 deaths at the more realistic 70 percent threshold: and this is a highly conservative estimate on a best-case scenario which is entirely hypothetical.


Healthcare Collapse

In summary, the most realistic fatality estimates for herd immunity would see around 15,000 younger people die in the UK, and 50,000 younger people die in the US. But the proponents of the Great Barrington Declaration do not discuss such figures. They do not admit that, in reality, colossal numbers of younger people will be inevitably be killed by this herd immunity approach.

And these estimates are based on the idea that a herd immunity strategy would actually work – we haven’t accounted for the likelihood that shielding elderly people from lines of transmission with younger people would be impracticable, resulting in COVID-19 spreading to significant numbers of them anyway. And we haven’t considered whether immunity acquired through infection is of a sufficient quality to contribute to herd immunity. When we do that, then we are left with Yamey’s estimate.

In a scenario where 129 million Americans and 13 million Britons are infected with COVID-19, it will be impossible to contain the virus away from the old and vulnerable. 

During this process of uncontrolled spread among younger people, even while most will not get severely ill, hundreds of thousands if not millions more would still require hospitalised. The hospitalisation rate for Americans in this age group, for instance, is between 14 and 20 percent. That’s a minimum of 18 million people hospitalised in the US. As the rate will be somewhat similar in the UK, we can reasonably expect some 1.8 million hospitalisations in the UK.

This scenario would see the US and UK healthcare systems face paralysis and collapse on an unprecedented scale. As healthcare collapses, death rates would drive up, and the conservative fatality estimates for young people offered here would go up as people can no longer receive hospital treatment. The impact on the workforce would be grave, and result in ramifying consequences across interconnected economic sectors.

Both countries’ currencies could go into free-fall as their stock markets plunge while investors flee a rapidly deteriorating situation, which could trigger further unpredictable consequences across other social and political sectors in the form of widespread unrest. The situation would be out of control and would probably be widely recognised as so unacceptable that lockdowns would be implemented anyway in the last resort, with further devastating economic impacts, though at such a later point in time they would be far less effective in controlling the virus. 


Long Term Economic Impacts – Health, GDP and the Over 50s

The implications of this analysis are stark. Even if all the speculative, unproven assumptions put forward by the proponents of a herd immunity strategy are correct (and as The Lancet open letter proves, most medical and public health experts disagree) the execution of this strategy will not avoid mass deaths, and associated economic dislocation, but will accelerate them.

The herd immunity strategy would play out in the following way: tens of thousands of deaths, millions of hospitalisations, collapsing healthcare systems, rapidly opening lines of transmission with elderly and vulnerable groups, further exponential epidemic growth, and a tremendous disaster as elderly and vulnerable find they cannot get the hospital treatment they need – driving fatality rates even higher.

Not only would this make Yamey’s estimate of 2.5 million Americans potentially dead from a COVID-19 strategy look like an underestimate, but it also does not even begin to look at the hundreds of thousands young adults who could end up suffering from ‘long COVID’ including symptoms such as fatigue, heart risk and chronic organ damage. 

All this would of course have devastating long-term economic imapcts.

It is widely recognised based on extensive data from 1960 until 2015, that health is directly correlated with GDP. Although the correlation is complicated, the data demonstrates that significant declines in health performance for populations will translate into significant drops in economic performance.

“The data clearly reveals a strong positive correlation between health and GDP,” points out a study lead-authored by Professor David E. Bloom of Harvard TH Chan School of Public Health. “Countries with better health status tend to have higher incomes than countries with worse health status, a relationship known as the ‘Preston curve’,” the study concludes, adding that health and income are “positively correlated across countries”, such that “life expectancy and income increased between 1960 and 2015.” 

While close correlations between GDP and health do begin to break down for more developed economies, and there is an ongoing debate about causality, what cannot be disputed is that the huge decline in national health represented by a herd immunity scenario, even with shielding, will result in both a massive decline in national life expectancy and a correlating collapse in GDP.

Of course, the other dimension of the economic problem which the herd immunity proponents overlook is the economic impact of shielding.

The economic contribution of people over the age of 50 to the US economy is huge. In 2018, they contributed a whopping 40 percent of the country’s GDP through both direct and indirect work, including support provided to family, friends and communities. In the UK, the situation is similar, with people over 75 increasing their spending into the economy far more than younger people. By 2040, they could end up contributing 63p for every pound to the economy. A near indefinite shielding strategy promises to permanently shutter away this massive economic motor, taking out a potential near 40 percent chunk of GDP. The herd immunity strategy would therefore not only kill younger people, and old. It would kill the economy.

No one has really attempted to model such outcomes. In this context, the idea that efforts to suppress the virus will produce more death and less economic problems than a policy of herd immunity, is simply unfounded.


Endless Lockdown

Does this mean that the only solution is an endless draconian lockdown? Well, no one is calling for that.

The Lancet open letter sees restrictions as a “short term” solution to get us to a point where we can implement longer-lasting measures that allow a return to normality.

“The purpose of these restrictions is to effectively suppress SARS-CoV-2 infections to low levels,” it explains. Once achieved, this would “allow rapid detection of localised outbreaks and rapid response through efficient and comprehensive find, test, trace, isolate, and support systems so life can return to near-normal without the need for generalised restrictions. Protecting our economies is inextricably tied to controlling COVID-19. We must protect our workforce and avoid long-term uncertainty.”

In fact, the best case scenarios show that the suite of solutions that can help countries return to a semblance of economic normality involve some variations of minimal restrictions with only temporary limited lockdowns, combined with very robust test, trace and isolate policies premised on strong community-embedded local public health infrastructure, along with strict border controls to keep new infusions of the virus at bay.

As the Lancet open letter points out, these are how countries like Australia, New Zealand, Germany, South Korea, Taiwan, Vietnam, Singapore and so on have been able to suppress the virus while keeping their economies alive, saving as many lives and livelihoods as possible.

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