COVID Blind-Spot: The Data Demands We Recognize Natural Immunity

Robert Nelson, MD

August 28, 2021

Publisher, Forum for Healthcare Freedom


Many physicians, epidemiologists and scientists, myself included, have been writing and speaking out for months about the validity and benefits of naturally derived immunity to COVID19. Limiting the conversation to only those who have received the vaccine is shortsighted at best and irresponsible public policy at worst. Moreover, focusing strictly on vaccine-induced immunity betrays a blind-spot for the past 70 years of immuno-virology research.

Collective immunity = Recoverees + Vaccinated

That calculus has always existed.  Let’s look at the evidence in detail.

Jeffrey Klausner, MD, MPH, and Noah Kojima, MD make this point eloquently in their Op-Ed: Quit Ignoring Natural COVID Immunity | MedPage Today

“The range of reduction of re-infection from COVID-19 was between 82% to 95% among six studies that encompassed nearly 1 million people conducted in the U.S., the U.K.DenmarkAustriaQatar, and among U.S. Marines. The study in Austria also found that the frequency of re-infection from COVID-19 caused hospitalization in only five out of 14,840 (0.03%) people and death in one out of 14,840 (0.01%).


Dr. Marty Makary also drives home this message with a timely well documented essay in the WSJ.

Ignoring decades of historical observations and volumes of empiric research on natural immunity to viral pathogens, essentially excluding it from the COVID19 conversation, is not a credible position. It never was.

The Faucian Doctrine of… we just don’t know anything for sure therefore we must take every imaginable precaution, even if shown to be ineffective…,is no longer credible. Elected officials have coerced citizens into participating in strategies that were proven, early in the pandemic, to be ineffective; while demanding we take our marching orders from the ever-changing non-science-based opinions of the official technocrats. This anti-rational bob & weave rope-a-dope strategy destroyed the livelihood of tens of millions in the U.S. and caused long term suffering of families & children. This charade must be rejected permanently.

To add insult to injury, 55 professional & scientific societies, including the American Hospital Association and the AMA, have called for mandatory vaccines (irrespective of previous infection).  The leadership of these organizations have apparently forgotten the indispensable role that natural immunity plays in combating any pandemic.  More recently, even the federal government has joined the vaccine ideologues with the President Biden mandating COVID vaccine for all federal employees. This is further proof that the psychology of mobs can afflict those of higher educational levels & professional societies!

If the vaccine is supposed to stimulate our immune system to fight off the virus more effectively (which I agree that it does) then how much more is the response of the immune system from a person who has recovered from the natural infection? Well, now we have some data to help answer that question and lay to rest any further talk of vaccine passports!  This data clearly indicates an advantage to natural immunity. Here is the summary from the study out of Israel:

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. 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.

Certainly, no thoughtful person is suggesting that those at high-risk for complications or death from SARS-CoV-2 should take their chances with natural infection in the hope of obtaining more robust immunity. But the equally important caveat is that those who have recovered should be viewed as being naturally “vaccinated” and not treated as second-class citizens or second-tier employees.

As with other diseases (Hep B, Measles, Chicken Pox, Rubella), many employers/hospitals accept proof of previous disease or immunity via positive serology in lieu of vaccination.  Why isn’t this being presented as option B to healthcare workers who have already had COVID19? Why do calls for vaccine mandates seem to always stop short of the larger issue, Immunity?

If an otherwise healthy person has successfully recovered from COVID, and based on the over-whelming evidence below (both hard immunologic data and epidemiologic data) if they are asymptomatic and test negative they are not a risk to anyone, regardless of mask or face shield.  The chance of them shedding infectious virus in that scenario approaches zero. 

After an extensive review of the literature, I find no compelling reason to suggest that those who have recovered from COVID-19, with intact immunes systems, require (or benefit long-term from) the COVID vaccine.  Some evidence indicates that side-effects, both local and systemic, from vaccine are higher in those who have had the infection.

And from Emory University, a study published in Cell Reports Medicine, the authors state:

“The picture that emerges indicates that the body’s defense shield not only produces an array of neutralizing antibodies but activates certain T and B cells to establish immune memory, offering more sustained defenses against reinfection.”

“We saw that antibody responses, especially IgG antibodies, were not only durable in the vast majority of patients but decayed at a slower rate than previously estimated, which suggests that patients are generating longer-lived plasma cells that can neutralize the SARS-CoV-2 spike protein.”

“Ahmed says investigators were surprised to see that convalescent participants also displayed increased immunity against common human coronaviruses as well as SARS-CoV-1, a close relative of the current coronavirus. The study suggests that patients who survived COVID-19 are likely to also possess protective immunity even against some SARS-CoV-2 variants.”

Anyone who wishes to get the vaccine has had ample opportunity to receive it.  Most of those at risk have been vaccinated; over 80% of adults 65 years or older have received the vaccine.  172 million citizens over age 12 have received the vaccine.  Estimates indicate that between 65 to 100 million people in the USA have recovered from COVID. Based on this reality, public and private policies should be geared towards more liberty and loosened restrictions, not tightening down more.

In my opinion, it is time to start living and behaving as if we believe in the effectiveness of the vaccines AND natural immunity, while taking proper precautions as deemed necessary in specific at-risk situations.  

For those who want to tap into their inner data wonk, take a deep dive below!  It’s raw and messy.  Enter at your own risk!

The references and summaries below are detailed and numerous.  I’ve tried to present them in a format that can be read fairly quickly or scanned for certain issues/topics.  I’m sure there are studies missing that are relevant and credible, but the ones listed below represent a considerable body of evidence regarding the current understanding of  COVID-19 immunity related issues.  There is some redundancy and over-lap of topics.  It is my hope that everyone reading this will find the data reassuring and hopeful.  I encourage anyone who wishes a more in-depth view to read the entire studies at the links provided.

…the incidence rate of reinfection was estimated at 0.66 per 10,000 person-weeks (95% CI: 0.56–0.78). Incidence rate of reinfection versus month of follow-up did not show any evidence of waning of immunity for over seven months of follow-up.

There are clear indications that SARS-CoV-2 infection results in the production of memory immune cells, suggesting that the same thing is likely to be happening among vaccinated people.

Other aspects of immunity, such as the T cell response, will also play a role in controlling the virus. Even if antibody production fades, it’s possible that other aspects of the immune response can partially compensate.

·         Longitudinal analysis shows durable and broad immune memory after SARS-CoV-2 infection with persisting antibody responses and memory B and T cells: Cell Reports Medicine

·         Vaccinated and unvaccinated individuals have similar viral loads in communities with a high prevalence of the SARS-CoV-2 delta variant | medRxiv

·         Lasting immunity found after recovery from COVID-19 | National Institutes of Health (NIH)

The researchers found durable immune responses in the majority of people studied. Antibodies against the spike protein of SARS-CoV-2, which the virus uses to get inside cells, were found in 98% of participants one month after symptom onset. As seen in previous studies, the number of antibodies ranged widely between individuals. But, promisingly, their levels remained fairly stable over time, declining only modestly at 6 to 8 months after infection.

Virus-specific B cells increased over time. People had more memory B cells six months after symptom onset than at one month afterwards. Although the number of these cells appeared to reach a plateau after a few months, levels didn’t decline over the period studied.

Levels of T cells for the virus also remained high after infection. Six months after symptom onset, 92% of participants had CD4+ T cells that recognized the virus. These cells help coordinate the immune response. About half the participants had CD8+ T cells, which kill cells that are infected by the virus.

As with antibodies, the numbers of different immune cell types varied substantially between individuals. Neither gender nor differences in disease severity could account for this variability. However, 95% of the people had at least 3 out of 5 immune-system components that could recognize SARS-CoV-2 up to 8 months after infection.

“Several months ago, our studies showed that natural infection induced a strong response, and this study now shows that the responses last,” Weiskopf says. “We are hopeful that a similar pattern of responses lasting over time will also emerge for the vaccine-induced responses.”

According to the results of the study, the reinfection rate for people who already had natural infection (as opposed to immunity via vaccination) was just two per 10,000, or 0.02%, with 99.98% of participants who were infected before not becoming infected a second time at any point during the 35-week tracking period.

In addition, the study found that when reinfection did occur, it tended to be less severe than initial infections, with just one case in the sample of 43,044 in which a person suffered a severe case of COVID after having previously been infected. Two other moderate cases were reported among those with reinfections. No fatal cases were reported among those with reinfections.

“Reinfection is rare,” the authors of the study concluded. “Natural infection appears to elicit strong protection against reinfection with an efficacy >90% for at least seven months.”

“Incidence rate of reinfection versus month of follow-up did not show any evidence of waning of immunity for over seven months of follow-up. Efficacy of natural infection against reinfection was estimated at >90%. Reinfections were less severe than primary infections.”

Previous SARS-CoV-2 exposure increased the odds of developing clinically significant symptoms following the first dose of a COVID-19 mRNA vaccine, researchers reported in JAMA Internal Medicine. “These vaccines can elicit greater local and systemic reactions in persons with prior SARS-CoV-2 infection,” Amanda K. Debes, PhD, MS, an assistant scientist in the department of international health at the Johns Hopkins Bloomberg School of Public Health, and colleagues wrote. “Whether symptoms following vaccination are associated with effectiveness is unknown, and, therefore, anxiety can arise in persons who did not develop a reaction following vaccination.”

The study examined some 12,000 health care workers who were infected with the coronavirus, then recovered. While some of the subjects developed antibodies, according to the serological tests, others did not. The results of the serological tests, however, gave little indication of overall immunity, the study found. Despite many of the subjects having no measurable COVID antibodies, reinfections were found to be extremely rare.

“We have no data which would indicate that the level of antibodies found by the various commercially available tests distinguishes between people who are immune after recovery and those who are not.”

“A person who recovered is to be considered as being immune, even if he has received negative [antibody] serological tests,” the authors concluded, arguing that serological testing should be ended for recovered coronavirus patients.

This is the second recent study which has found that reinfections are rare following natural infection with the coronavirus.

A study of 43,044 people tracked for up to 35 weeks in Qatar found that just 0.02% experienced reinfection, suggesting that natural infection creates a high level of immunity for an extended period of time.

the study

A new study on the effects of natural infection by the coronavirus suggests that there may be little to no benefit for recovered SARS-CoV-2 patients in receiving vaccines against the coronavirus.

According to the study, conducted in Cleveland, Ohio and published in the MedRxiv journal last month, people who were infected with the coronavirus enjoy significant long-term immunity from the virus, which is unlikely to be increased by being injected with one of the coronavirus vaccinations now on the market.

The study followed 52,238 employees of the Cleveland Clinic Health System, monitoring infections among vaccinated and unvaccinated workers, and the incidents of reinfection among both vaccinated and unvaccinated workers.

Of the 52,238 employees tracked in the study, 2,579 had previously tested positive for the coronavirus, while 49,659 had never been confirmed as carrying the virus.

Fifty-three percent of the 2,579 employees who had been infected with the virus previously remained unvaccinated (1,359 people), compared to 41% (22,777) of the employees who were never diagnosed with the virus.

Zero previously infected employees were reported to have become infected again with the virus, regardless of their vaccination status.

Vaccination significantly reduced the risk of coronavirus infection, the study found, but only among those who had not previously been infected.

The authors concluded that vaccination after natural infection is unlikely to have any benefit for recovered COVID patients.

The following are some of the data and studies regarding immunity acquired after Covid infection.

Longitudinal analysis shows durable and broad immune memory after SARS-CoV-2 infection with persisting antibody responses and memory B and T cells, July 20, 2021

This study followed 254 Covid-19 patients for up to 8 months and concluded they had “durable broad-based immune responses.” In fact, even very mild Covid-19 infection also protected the patients from an earlier version of “SARS” coronavirus that first emerged around 2003, and against Covid-19 variants. “Taken together, these results suggest that broad and effective immunity may persist long-term in recovered COVID-19 patients,” concludes the study scientists.

Associations of Vaccination and of Prior Infection With Positive PCR Test Results for SARS-CoV-2 in Airline Passengers Arriving in Qatar, June 9, 2021 

This study of airline passengers in Qatar found that both vaccination and prior infection were “imperfect” when it comes to preventing positive Covid-19 test results, but that the incidence of reinfection is similarly low in both groups.

Necessity of COVID-19 vaccination in previously infected individuals, June 1, 2021

This study followed 52,238 employees of the Cleveland Clinic Health System in Ohio. 

For previously-infected people, the cumulative incidence of re-infection “remained almost zero.” According to the study, “Not one of the 1,359 previously infected subjects who remained unvaccinated had a [Covid-19] infection over the duration of the study” and vaccination did not reduce the risk. “Individuals who have had [Covid-19] infection are unlikely to benefit from COVID-19 vaccination,” concludes the study scientists.

SARS-CoV-2 specific memory B-cells from individuals with diverse disease severities recognize SARS-CoV-2 variants of concern, May 29, 2021

This study found strong immune signs in people who had previously been infected with Covid-19, including “those [who] experienced asymptomatic or mild disease.” The study concludes there is “reason for optimism” regarding the capacity of prior infection “to limit disease severity and transmission of variants of concern as they continue to arise and circulate.”

A population-based analysis of the longevity of SARS-CoV-2 antibody seropositivity in the United States, May 24, 2021

This study of real world data extended the timeframe of available data indicating that patients have strong immune indicators for “almost a year post-natural infection of COVID-19.” The study concludes the immune response after natural infection “may persist for longer than previously thought, thereby providing evidence of sustainability that may influence post-pandemic planning.”

SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans, May 24, 2021

This study examined bone marrow of previously-infected patients and found that even mild infection with Covid-19 “induces robust antigen-specific, long-lived humoral immune memory in humans.” The study indicates “People who have had mild illness develop antibody-producing cells that can last lifetime.”

People who have had mild illness develop antibody-producing cells that can last lifetime.

World Health Organization (WHO) scientific brief, May 10, 2021

This scientific brief issued by WHO states that after natural infection with Covid-19, “available scientific data suggests that in most people immune responses remain robust and protective against reinfection for at least 6-8 months.”

Detection of SARS-CoV-2-Specific Humoral and Cellular Immunity in COVID-19 Convalescent Individuals, May 3, 2020

This study found humoral and cellular immunity in recovered Covid patients. “Production of S-RBD-specific antibodies were readily detected in recovered patients. Moreover, we observed virus-neutralization activities in these recovered patients,” wrote the study authors.

The adaptive immune system consists of three major lymphocyte types: B cells (antibody producing cells), CD4+ T cells (helper T cells), and CD8+ T cells (cytotoxic, or killer, T cells

From: Antigen-Specific Adaptive Immunity to SARS-CoV-2 in Acute COVID-19 and Associations with Age and Disease Severity

Protection of previous SARS-CoV-2 infection is similar to that of BNT162b2 vaccine protection: A three-month nationwide experience from Israel, April 24, 2021

This study from Israel found a slight advantage to natural infection over vaccination when it comes to preventing a reinfection and severe illness from Covid-19.

The study authors concluded, “Our results question the need to vaccinate previously-infected individuals.”

A 1 to 1000 SARS-CoV-2 reinfection proportion in members of a large healthcare provider in Israel: a preliminary report, March 6, 2021

This study found a rare Covid-19 positive test “reinfection” rate of 1 per 1,000 recoveries.

Lasting immunity found after recovery from COVID-19, Jan. 26, 2021

Research funded by the National Institutes of Health and published in Science early in the Covid-19 vaccine effort found the “immune systems of more than 95% of people who recovered from COVID-19 had durable memories of the virus up to eight months after infection,” and hoped the vaccines would produce similar immunity. (However, experts say they do not appear to be doing so.)

SARS-CoV-2 reinfection in a cohort of 43,000 antibody-positive individuals followed for up to 35 weeks, Jan. 15, 2021

This study found Covid-19 natural infection “appears to elicit strong protection against reinfection” for at least seven months. “Reinfection is “rare,” concludes the scientists.

Immunological memory to SARS-CoV-2 assessed for up to eight months after infection, Nov. 1, 2020

This study confirmed and examined “immune memory” in previously-infected Covid-19 patients.

Negligible impact of SARS-CoV-2 variants on CD4+ and CD8+ T cell reactivity in COVID-19 exposed donors and vaccinees, Nov. 1, 2020

This study concluded “T cell” immune response in former Covid-19 patients likely continues to protect amid Covid-19 variants.

Orthogonal SARS-CoV-2 Serological Assays Enable Surveillance of Low-Prevalence Communities and Reveal Durable Humoral Immunity, Oct. 13, 2020

This study found that “neutralizing antibodies are stably produced for at least 5–7 months” after a patient is infected with Covid-19.

SARS-CoV-2-specific T cell immunity in cases of COVID-19 and SARS, and uninfected controls, July 25, 2020

This study found that all patients who recently recovered from Covid-19 produced immunity-strong T cells that recognize multiple parts of Covid-19.

They also looked at blood samples from 23 people who’d survived a 2003 outbreak of a coronavirus: SARS (Cov-1). These people still had lasting memory T cells 17 years after the outbreak. Those memory T cells, acquired in response to SARS-CoV-1, also recognized parts of Covid-19 (SARS-CoV-2).

Much of the study on the immune response to SARS-CoV-2, the novel coronavirus that causes COVID-19, has focused on the production of antibodies. But, in fact, immune cells known as memory T cells also play an important role in the ability of our immune systems to protect us against many viral infections, including—it now appears—COVID-19.

“Immune T Cells May Offer Lasting Protection Against COVID-19”

At a Glance

  • The immune systems of more than 95% of people who recovered from COVID-19 had durable memories of the virus up to eight months after infection.
  • The results provide hope that people receiving SARS-CoV-2 vaccines will develop similar lasting immune memories after vaccination.


  • Most recovered COVID-19 patients mount broad, durable immunity after infection
  • Neutralizing antibodies show a bi-phasic decay with half-lives >200 days
  • Spike IgG+ memory B cells increase and persist post-infection
  • Durable polyfunctional CD4 and CD8 T cells recognize distinct viral epitope regions

At a Glance

  • A study of blood samples taken before the COVID-19 pandemic showed that some people already had certain immune cells that recognize SARS-CoV-2.
  • These immune cells also reacted with coronaviruses that cause common colds.
  • The findings suggest that existing immune cells may help account for the wide range of symptoms experienced by people with COVID-19.


A previous history of SARS-CoV-2 infection was associated with an 84% lower risk of infection, with median protective effect observed 7 months following primary infection. This time period is the minimum probable effect because seroconversions were not included. This study shows that previous infection with SARS-CoV-2 induces effective immunity to future infections in most individuals.

We found that magnitude varied amongst individuals, but was the highest in hospitalized subjects. Variants of concern (VoC) -RBD-reactive antibodies were found in the plasma of 72% of samples in this investigation, and VoC-RBD-reactive memory B-cells were found in all but 1 subject at a single time-point. This finding, that VoC-RBD-reactive MBCs are present in the peripheral blood of all subjects including those that experienced asymptomatic or mild disease, provides a reason for optimism regarding the capacity of vaccination, prior infection, and/or both, to limit disease severity and transmission of variants of concern as they continue to arise and circulate.

Conclusions Individuals who have had SARS-CoV-2 infection are unlikely to benefit from COVID-19 vaccination, and vaccines can be safely prioritized to those who have not been infected before.

Out of 149,735 individuals with a documented positive PCR test between March 2020 and January 2021, 154 had two positive PCR tests at least 100 days apart, reflecting a reinfection proportion of 1 per 1000. Given our strict inclusion criteria, we believe these numbers represent true reinfection incidence in MHS and should be clinically regarded as such.

Overall, our results indicate that mild infection with SARS-CoV-2 induces robust antigen-specific, long-lived humoral immune memory in humans.

Here we studied T cell responses against the structural (nucleocapsid (N) protein) and non-structural (NSP7 and NSP13 of ORF1) regions of SARS-CoV-2 in individuals convalescing from coronavirus disease 2019 (COVID-19) (n = 36). In all of these individuals, we found CD4 and CD8 T cells that recognized multiple regions of the N protein. Next, we showed that patients (n = 23) who recovered from SARS (the disease associated with SARS-CoV infection) possess long-lasting memory T cells that are reactive to the N protein of SARS-CoV 17 years after the outbreak of SARS in 2003; these T cells displayed robust cross-reactivity to the N protein of SARS-CoV-2


SARS-CoV-2-specific antibodies are detected in COVID-19 convalescent subjects

Most COVID-19 convalescent individuals have detectable neutralizing antibodies

Cellular immune responses to SARS-CoV-2 are found in COVID-19 convalescent subjects

Neutralization antibody titers correlate with the numbers of virus-specific T cells.

In the absence of vaccination, antibody reactivity to the receptor binding domain (RBD) of SARS-CoV-2, neutralizing activity and the number of RBD-specific memory B cells remain relatively stable between 6 and 12 months after infection. 


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