Can Herd Immunity End the Pandemic?

By Roger Chriss, PNN Columnist

The latest round in the ongoing public health debate over the pandemic pits two online petitions against each other: the "Great Barrington Declaration" versus the “John Snow Memorandum.” The former focuses on natural herd immunity, while the latter emphasizes controlling community spread through lockdowns, masks and other public health measures.

The Barrington Declaration has garnered support from the Trump administration because it calls for schools and businesses to reopen, and for life to return to normal for “those who are not vulnerable” to the virus.

“The most compassionate approach that balances the risks and benefits of reaching herd immunity, is to allow those who are at minimal risk of death to live their lives normally to build up immunity to the virus through natural infection, while better protecting those who are at highest risk. We call this Focused Protection,” the Declaration states.

The John Snow Memorandum, named for the famed British physician who halted the 1854 London cholera outbreak, states that "Any pandemic management strategy relying upon immunity from natural infections for COVID-19 is flawed. Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population."

The Declaration’s Fundamental Flaws

The Declaration claims that “all populations will eventually reach herd immunity – i.e. the point at which the rate of new infections is stable – and that this can be assisted by (but is not dependent upon) a vaccine.”

But we do not know this. Many diseases, from malaria to Ebola, continue to rip through populations without reaching herd immunity. It is entirely possible that Covid-19 will reach a similarly perilous “equilibrium,” becoming endemic until the arrival of a vaccine. At this point we don’t know enough about the coronavirus SARS-CoV-2 to make any strong claims that herd immunity will “eventually” happen.

Moreover, the “Focused Protection” championed in the declaration assumes that we have adequate testing, contact tracing and isolating to protect the vulnerable, though at present the U.S. does not. It further assumes that Covid-19 doesn’t have a significant disease burden, even though there is mounting evidence that the disease can cause considerable and long-lasting harm in otherwise healthy adults and children.

The Declaration assumes that durable immunity to the virus results from infection. But there are a handful of documented cases where reinfection has occurred, such as a 25-year old Nevada man who became seriously ill during his second bout with Covid-19.  It’s not clear how “durable” immunity is.

As Yale immunologist Akiko Iwasaki explains in a recent commentary in The Lancet, “reinfection cases tell us that we cannot rely on immunity acquired by natural infection to confer herd immunity; not only is this strategy lethal for many but also it is not effective."

The experiences of Arizona, Florida and Texas over the summer show that “Focused Protection” doesn’t work in the real world. All three states were hit hard during the summer surge, with hundreds of thousands of cases and tens of thousands of deaths. As we head into the fall, we’re now seeing a surge of new cases in the upper Midwest.

The Memorandum’s Practical Challenge

The John Snow Memorandum states that “controlling community spread of COVID-19 is the best way to protect our societies and economies until safe and effective vaccines and therapeutics arrive within the coming months.”

This is credible, given the experiences of Germany, New Zealand, South Korea and other nations that managed to control virus spread and minimize death and disease through a mixture of public health measures. They created national plans for testing, tracing and isolating, and with consistent public health messaging that minimized socioeconomic disruption. Lockdowns were not always necessary, either. Japan avoided a national lockdown, instead controlling spread with strong public health measures.

The United States, by contrast, has failed to do these things. We are not generally good at public health, as the worsening opioid overdose crisis has clearly shown. The failures in the overdose crisis were arguably prologue for the uncoordinated and undisciplined approach the U.S. has taken to the pandemic.

The Memorandum’s recommendations are laudable, but they will be hard to implement, even though current projections suggest over 170,000 more deaths and millions of new cases of Covid-19 in the coming months.

The U.S. needs to ask itself two questions. First, how did we get to a point where the Great Barrington Declaration even sounds like a good idea? Second, what can we do to find a better way forward, as suggested by the John Snow Memorandum, to avoid additional deaths and disease? Winter is coming and the coronavirus will have the run of the country unless we step up to stop it.

Roger Chriss lives with Ehlers Danlos syndrome and is a proud member of the Ehlers-Danlos Society. Roger is a technical consultant in Washington state, where he specializes in mathematics and research.