September 9, 2021 Reading Time: 6 minutes

A growing body of research is making it increasingly clear that natural immunity to Covid-19 owing to previous infection is stronger, more durable, and broader than vaccine-induced immunity. Apart from not being unusual among infectious diseases, this fact has significant implications for governmental, school, employer, and business plans to harass and restrict people who aren’t vaccinated.

For example, on June 4 Stanford Medical School physician and economist Jay Bhattacharya, Harvard Medical School biostatistician and epidemiologist Martin Kulldorff, and University of Oxford theoretical epidemiologist Sunetra Gupta summarized it this way (embedding several studies along the way):

It is now well-established that natural immunity develops upon infection with SARS-CoV-2 in a manner analogous to other coronaviruses. While natural infection may not provide permanent infection-blocking immunity, it offers antidisease immunity against severe disease and death that is likely permanent. Among the millions that have recovered from COVID19, exceedingly few have become sick again.

Most recently, new research out of Israel makes the case that a prior Covid-19 infection offers far superior immunity than do the vaccinations. Gazit et al. (medRxiv preprint, posted Aug. 25, 2021) compared vaccinated people without prior Covid-19 infections with unvaccinated people who had recovered from prior infections. Matching them by infection/vaccination periods to test their “immune activation” time (16,125 people in each group; i.e., 32,250 people), they found the vaccinated were six to 13 times more likely to have breakthrough infections than were the naturally immune to have reinfection. Adjusting for comorbidities, they found the vaccinated were 27 times more likely to have symptomatic breakthrough infections than were the naturally immune to have symptomatic reinfection.

Furthermore, there is reason to believe that for the previously infected, vaccination could be detrimental to their immune response. Camara et al. (bioRxiv preprint, posted March 22, 2021) found that “COVID-19 recovered individuals do not seem to benefit from the standard regimen for COVID-19 vaccination.” As they wrote, “On the contrary, in individuals with a pre-existing immunity against SARS-CoV-2, the second vaccine does not only fail to boost humoral immunity but determines a contraction of the spike-specific T cell response.” For the previously infected, then, there is reason to believe that the vaccine poses no benefits, only costs.

George Mason law professor Todd Zywicki had several compelling reasons behind his successful challenge to his university’s vaccine mandate. As seen by the July 21 letter on his behalf from the New Civil Liberties Alliance, Zywicki was previously infected, offered substantial research attesting that immunity to Covid-19 through infection was “at least as robust and long lasting as that achieved through vaccination,” had evidence to be wary of adverse reactions given his recent bout with shingles, and was also concerned that all of the vaccine trials so far had specifically excluded survivors of prior Covid-19 infections, citing a study in which researchers stated “we cannot exclude the possibility that the vaccination of a growing number of [individuals] with preexisting immunity to SARS-Cov-2 may trigger unexpectedly intense, albeit very rare, inflammatory and thrombotic reactions in previously immunized and predisposed individuals” (Angeli et al., European Journal of Internal Medicine, June 2021).

It shouldn’t need to be said, except in this bizarre time in which things that “shouldn’t need to be said” are the very things that require clear statement, but such research and discussion is in no way meant to counsel against vaccination, which ought to be a personal decision based on a dispassionate weighing of personal benefits and costs without coercion. Nor is it to argue for deliberately contracting an infection. I have personally witnessed this presentation of facts carom around inside someone’s skull until it comes out bruised and twisted into “Oh sure, go get Covid and die, then you’ll be immune!”

These findings stand in stark contrast to the case for “vaccine passports,” the euphemism for depersoning anyone who hasn’t taken a vaccine against Covid-19. Pres. Joe Biden has talked of banning interstate travel to the unvaccinated. Universities are barely waiting for the tuition checks to clear before imposing vaccination mandates. Hospitals, health care facilities, on down to rehabilitation facilities, are denying critical care services to the unvaccinated, who are also finding themselves in some places at risk of losing access to government services. Governments, schools, hospitals, and some businesses — egged on by politicians, public health popinjays, and media — are threatening the very jobs of the unvaccinated (with those deadlines looming, September could be a bad month for job losses). Even some retailers, restaurants, entertainment venues, and others are denying their services to the unvaccinated.

Again and again, these tyrannical edicts make no allowances for people with natural immunity. Should the people behind them get credit for caring, for trying to further public health? Their defense, after all, is that they’re trying to pressure people to do what’s good for them; e.g., the White House considers vaccine mandates “the right lever at the right time.” How much goodwill shall we ascribe to them amid such pointless, callous behavior? The person turned away at the schoolhouse door, the person denied critical medical care, the person not allowed in your restaurant, the person forbidden from fleeing to a freer state — that person without a vaccination card could very well carry a stronger immune response against the virus than the card-carrying elite allowed to participate in your Unbrave New World.

Oh, but the response is, unlike with the vaccinated, it’s hard to know who has recovered from previous infection. Right, and that fact undercuts the case for “vaccine passports” as well. Let me explain how.

The Centers for Disease Control and Prevention estimates that only 1 out of every 4.2 actual infections of Covid-19 are reported in the U.S. This estimate makes sense if you consider, for example, one member of a family of four tests positive but the rest in the house feel sick, or also so many mild or asymptomatic infections that wouldn’t prompt a doctor’s visit (those are, incidentally, signs of “a highly functional virus-specific cellular immune response,” per Le Bert et al., Journal of Experimental Medicine, March 1, 2021).

As of this writing, there have been nearly 39,280,000 cases (i.e., reported infections) and nearly 639,000 deaths. Multiply the case count by 4.2 and then subtract out deaths, and that implies there are about 164.3 million people with robust natural immunity. That is nearly half of the population in the U.S. already (332.7 million per U.S. Census Bureau estimates as of this writing).

Without accounting for vaccination, then, roughly half of the U.S. population already has an immunity to Covid-19 that is stronger, more durable, and broader than anything from a vaccine. Only about one-fourth of them, however, would be able to “prove” it with documentation of a reported case.

So yes, it’s “hard to know” who’s already got natural immunity. That uncertainty, however, targets half the country when it comes to denying them common human decency and the mundane privileges of traveling, attending university, receiving medical care, receiving government services, dining out, or even buying groceries.

Such acts are made with the presumption that there is no good reason not to get a vaccine. To be sure, there are several good reasons to choose vaccination, especially if you are among those in vulnerable groups such as the elderly and those with chronic disease. But as Zywicki showed, there are also good, compelling reasons that someone might decide against vaccination.

As Kulldorff and Bhattacharya wrote in The Wall Street Journal on April 6,

The idea that everybody needs to be vaccinated is as scientifically baseless as the idea that nobody does. Covid vaccines are essential for older, high-risk people and their caretakers and advisable for many others. But those whoʼve been infected are already immune. The young are at low risk, and children—for whom no vaccine has been approved anyway—are at far less risk of death than from the flu. If authorities mandate vaccination of those who donʼt need it, the public will start questioning vaccines in general…

Vaccine passports are unjust and discriminatory. Most of those endorsing the idea belong to the laptop class—privileged professionals who worked safely and comfortably at home during the epidemic. Millions of Americans did essential jobs at their usual workplaces and became immune the hard way. Now they would be forced to risk adverse reactions from a vaccine they donʼt need. Passports would entice young, low-risk professionals, in the West and the developing world, to get the vaccine before older, higher-risk but less affluent members of society. Many unnecessary deaths would result.

The right response in these uncertain times is — as always — the response that protects people’s liberty and respects their autonomy. Fight “vaccination passports” and similar mandates forbidding people from enjoying all the privileges they enjoyed as a matter of course prior to March 2020. Resist the urge to burden your employees, students, patients, and patrons. Even taken on their own merits, these prohibitions amount to nothing more than a coin flip against each and every person turned away. Considered in full, they are cruel, discriminatory, and ultimately self-defeating.

Jon Sanders

Jon Sanders

Jon Sanders is an economist and the senior fellow of regulatory studies and research editor at the John Locke Foundation in Raleigh, North Carolina.

Jon researches a broad range of areas, including energy and electricity policy, occupational licensing, red tape and overregulation, alcohol policy, executive orders and overreach, poverty and opportunity, cronyism and other public-choice problems, emerging ideas and economic growth, and other issues as they arise.

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