How the White House’s Herd Immunity Strategy Would Destroy the US Economy

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.

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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.  

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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.”

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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.

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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.

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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