Vaccine mandates

Even If Requiring People Who Have Recovered From COVID-19 To Be Vaccinated Is Legal, That Doesn't Mean It Makes Sense

The failure of legal challenges obscures an ongoing scientific debate.


A federal judge on Friday rejected a Michigan State University (MSU) employee's motion for a preliminary injunction against the school's requirement that staff members be vaccinated against COVID-19. Jeanna Norris, an administrator at the school, argued that her "naturally acquired immunity" made the mandate "unlawful" as applied to her and other staffers who have recovered from the disease. U.S. District Judge Paul Maloney concluded that, notwithstanding the scientific evidence that Norris cited to support her position, the public university's policy easily satisfied the "rational basis" test.

That standard of review is highly deferential, so it is not surprising that Norris, who is represented by the New Civil Liberties Coalition, did not get the injunction she wanted. Maloney notes that the Supreme Court applied what was essentially a rational basis test (although that term had not been invented yet) in the 1905 case Jacobson v. Massachusetts, which involved a state-authorized requirement that Cambridge residents be inoculated against smallpox or pay a $5 fine (equivalent to about $155 today).

Maloney rejected Norris' argument that the vaccination requirement violates her fundamental rights to privacy and bodily integrity, which would have triggered strict scrutiny under the 14th Amendment, a much more demanding standard of review. "Plaintiff is absolutely correct that she possesses those rights, but there is no fundamental right to decline a vaccination," he writes. "She also does not have a constitutionally protected interest in her job at MSU, which Plaintiff's counsel conceded. The MSU vaccine policy does not force Plaintiff to forgo her rights to privacy and bodily autonomy, but if she chooses not to be vaccinated, she does not have the right to work at MSU at the same time."

That analysis suggests why similar legal challenges by people with naturally acquired COVID-19 immunity are unlikely to succeed in court. But it does not settle the question of whether mandates like MSU's, even if "rational" in the legal sense, are fair or reasonable in light of the scientific evidence.

Norris "has already contracted and fully recovered from COVID-19," her complaint says. "As a result, she has naturally acquired immunity, confirmed unequivocally by two recent SARS-CoV-2 antibody tests. Her immunologist, Dr. Hooman Noorchashm, has advised her that it is medically unnecessary to undergo a vaccination procedure at this point."

Maloney heard from dueling scientific experts on the question of how much protection prior infection confers. "There is ongoing scientific debate about the effectiveness of naturally acquired immunity versus vaccine immunity," he writes. But he adds that "even if there is vigorous ongoing discussion about the effectiveness of natural immunity, it is rational for MSU to rely on present federal and state guidance in creating its vaccine mandate."

That legal conclusion is distinct from the policy question of whether it makes sense as a workplace safety measure to impose a vaccine mandate with no exception for people like Norris—an issue that could be important in evaluating the legality of the Biden administration's pending regulation demanding that companies with 100 or more employees require them to be inoculated or undergo regular coronavirus testing. That rule, which the White House announced a month ago, still has not been published. But it is not expected to include an exception for employees who have recovered from COVID-19.

The administration is relying on the authority that Congress gave the Occupational Safety and Health Administration (OSHA) to issue an "emergency temporary standard" when it is "necessary" to protect employees from "grave danger." The issue of whether unvaccinated people with natural immunity pose such a danger is therefore legally relevant. It is also relevant for employers who are deciding the details of their own policies.

A widely cited Israeli preprint study posted in August suggested that natural immunity is more effective than vaccination at preventing infection by the delta variant. The researchers studied the records of patients enrolled in Maccabi Healthcare Services, which covers 2.5 million Israelis, a quarter of the population. Compared to unvaccinated patients who had recovered from COVID-19 in January or February 2021, they found, vaccinated patients with no history of infection were 13 times as likely to be infected between June 1 and August 14, 2021, "when the Delta variant was dominant in Israel."

When the researchers included patients who had been infected at any point from March 2020 to February 2021, the difference in risk was smaller, suggesting that the protection from natural immunity wanes over time. But the "SARS-CoV-2-naïve vaccinees" were still six times as likely to be infected. "This study demonstrated that natural immunity confers longer lasting and stronger protection against infection, symptomatic disease and hospitalization caused by the Delta variant of SARS-CoV-2, compared to the BNT162b2 two-dose vaccine-induced immunity," the authors concluded.

Critics have pushed back against that conclusion, citing potential problems with the study's retrospective design. James Lawler, an infectious disease specialist at the University of Nebraska College of Medicine, has noted that the vaccinated patients were more likely than the unvaccinated patients to be elderly and to have preexisting health conditions that made them especially vulnerable to COVID-19. The researchers tried to take that selection bias into account, but Lawler argued in an August 31 briefing that their adjustments may not have been adequate. He added that unvaccinated patients who died from COVID-19 were not included in the study, which also might have skewed the results.

One point on which the Israeli researchers and U.S. public health officials agree is that vaccination is beneficial even for people with natural immunity. The authors of the Israeli study noted that "individuals who were both previously infected with SARS-CoV-2 and given a single dose of the vaccine gained additional protection against the Delta variant." A study that the Centers for Disease Control and Prevention published in August looked at Kentucky residents who had recovered from COVID-19, some of whom were subsequently vaccinated. The researchers found that unvaccinated people were more than twice as likely to be reinfected as fully vaccinated people.

But when it comes to vaccine mandates, the relevant question is whether an unvaccinated person with natural immunity is substantially more likely to catch and transmit the coronavirus than a vaccinated person without natural immunity. On that point, medical experts disagree.

Peter McCullough, a Dallas internist and cardiologist with a public health degree who testified in support of psychiatrist Aaron Kheriaty's unsuccessful challenge to the University of California's vaccine mandate, argued that the coronavirus "causes an infection in humans that results in robust, complete, and durable immunity"—a protective effect that is "superior to vaccination-induced immunity." McCullough emphasized that antibody tests reflect only part of the immune response to a COVID-19 infection, which includes "antibodies to the nucleocapsid and to the spike protein, as well as T-helper cells, natural killer cells, B-cells, and innate immunity."

By contrast, the Berkeley epidemiologist Arthur Reingold argued in the same case that the university's blanket vaccine requirement was justified because the strength and longevity of natural immunity are unclear. "While individuals who have had a documented case of COVID-19 typically have antibodies to the SARS-CoV-2 virus detectable in their blood and are believed to have a reduced risk of getting COVID-19 again in the months that follow," he said, "neither the completeness nor the durability of protection against a second case of COVID-19 has been established. The extent to which any such immunity resulting from having had COVID-19 provides protection against new variants of SARS-CoV-2 is also unknown."

The British Society for Immunology (BSI) offers a similar gloss. "It's likely that for most people vaccination against COVID-19 will induce more effective and longer lasting immunity than that induced by natural infection with the virus," it says. But the rest of its summary paints a more complicated picture.

The BSI says the immune response to a COVID-19 infection "varies hugely between people." Yet it also says the immune response to COVID-19 vaccine "varies," although "most" vaccinations "produce a strong immune response," even in "older people." The BSI thinks vaccination "may produce a more robust immune response."

The "length of protection" from natural immunity is "variable" and "not fully known," the BSI says. But "protection tends to be lower in people who were mildly ill," and it "reduces over time." The length of protection from vaccination likewise is "still to be learnt," although two-dose vaccines have "produce[d] long-term protection so far." Assuming that protection wanes (the issue at the center of the debate about who should receive boosters and when), "booster vaccines could maintain a strong immune response."

What about protection against variants? In people who have recovered from COVID-19, the BSI says, "reinfection [is] possible but uncommon." Since "response to natural infection is variable," the immune system "may not be able to recognize a viral variant." Two-dose vaccines "provide strong protection against many currently identified variants," which is more likely when "high antibody levels [are] produced."

In both cases, then, immune responses vary from one person to another, may fade over time, and provide some protection against variants. Overall, the advantages of vaccination compared to waiting for an infection are clear, especially since people who catch the virus can transmit it to others and may suffer severe symptoms. But that does not mean unvaccinated people who already have recovered from COVID-19 pose a significantly higher risk than vaccinated people with no prior infections.

A private employer might conclude that a blanket vaccine requirement is easier to administer than one that makes an exception for previously infected people. The latter approach presumably would require documentation of prior infections. It might also require evidence, similar to the tests cited by Norris, of a robust immune response—although vaccinated people don't have to produce such evidence, even though their immune responses also vary.

As a matter of public policy, however, that added complication does not seem unreasonably burdensome. The OSHA order described by the Biden administration already includes an exception for employees who agree to be tested at least once a week, which is more expensive and harder to arrange than a one-time requirement that employees document their COVID-19 histories.

Jeffrey Klausner, a clinical professor of population and public health sciences at the University of Southern California, co-authored a systematic review in the journal Evaluation & the Health Professions last month that found "the protective effect of prior SARS-CoV-2 infection on re-infection is high and similar to the protective effect of vaccination," although "more research is needed to characterize the duration of protection and the impact of different SARS-CoV-2 variants." While the existing evidence is incomplete, Klausner thinks it is strong enough to justify an exception to vaccine requirements. "From the public health perspective," he told Kaiser Health News, "denying jobs and access and travel to people who have recovered from infection doesn't make sense."