A new retrospective observational study conducted by researchers at Tel Aviv University and Maccabi Healthcare in Israel found that unvaccinated individuals who developed an infection with the SARS-CoV-2 virus were considerably more protected against the Delta variant of the virus than those who had received two doses of the Pfizer/BioNTech’s experimental messenger RNA (mRNA) biologic BNT162b2.1 2 3 4 5 6 7 8
According to the study, those who had been vaccinated with BNT162b2 were 13 times more likely to be infected with the Delta variant than those who had already been infected with the SARS-CoV-2 virus and had developed natural immunity to the virus. The study also found that vaccinated individuals were at a significantly higher risk of developing COVID-19 symptoms and being hospitalized for the illness than those with natural immunity.1 2 3 5 8
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.2 3 7
Study is Largest to Compare Natural and Vaccine-Induced Immunity
The study, which is the largest real-world observational study to date comparing natural and vaccine-induced immunity, was broken down into three categories: 673,676 individuals who received two doses of BNT162b2, 62,883 previously infected individuals who were unvaccinated and 42,099 previously infected individuals who received one dose of BNT162b2. All individuals observed were 16 years of age or older. 2 3 5 6
“It’s a textbook example of how natural immunity is really better than vaccination,” says Charlotte Thålin, MD of Danderyd Hospital and the Karolinska Institute in Sweden. “To my knowledge, it’s the first time [this] has really been shown in the context of COVID-19.”8
It is worth noting that the study has only been published as a preprint and has not yet been peer reviewed. The study also has some limitations. For example, it only examined Pfizer/BioNTech’s BNT162b2 shot, not other COVID biologics on the market. Also, while the study controlled for factors such as age, gender and area of residence, behaviors such as social distancing and mask wearing were not taken into account.2 3 6 7
Furthermore, the authors of the study noted, “as this is an observational real-world study, where PCR ( polymerase chain reaction) screening was not performed by protocol, we might be underestimating asymptomatic infections, as these individuals often do not get tested.”2
Study Confirms Findings in Published Papers
Still, the results of the study confirm similar results in peer-reviewed papers published in Nature and Immunity Physician and immunologist Michael Nussenzweig, MD, PhD of the Rockefeller University in New York City has published data in those journals showing that individuals who recover from infections with the SARS-CoV-2 virus “continue to develop increasing numbers and types of coronavirus-targeting antibodies for up to one year.”8 9 10
By comparison, Dr. Nussenzweig says, those who have received two doses of a COVID vaccine cease to have increases “in the potency or breadth of the overall memory antibody compartment” just a few months after the second dose.8
“It will be important to see these findings replicated or refuted,” says biostatistician Natalie Dean, PhD of Emory University in Atlanta, Georgia.8
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1 Bettermann E. STUDY: Natural immunity 13 times more effective than vaccines at stopping “delta” variant. DrEddyMD.com Sept. 2, 2021.
2 Gazit S, Shlezinger R, Perez G, Lotan R, Peretz A, Ben-Tov A, Cohen D, Muhsen K, Chodick G, Patalon T. Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections
3 Kekatos M. Natural immunity from Covid infection could be stronger than vaccination in protecting against Delta variant: Recovered patients are 13 TIMES less likely to be infected than those who have Pfizer jabs, Israeli study suggests. Daily Mail Aug. 27, 2021.
4 Miltimore J. Harvard Epidemiologist Says the Case for COVID Vaccine Passports Was Just Demolished. Foundation for Economic Education Aug. 30, 2021.
5 Richardson C. Au Naturel: Israel’s Immunity Study. The American Conservative Sept. 1, 2021.
6 The Rio Times. Scientific study from Israel shows natural immunity superior to Covid vaccine against Delta variant. Aug. 28, 2021.
7 UnHerd. ‘Bombshell’ study finds natural immunity superior to vaccination. Aug. 26, 2021.
8 Wadman M. Having SARS-CoV-2 once confers much greater immunity than a vaccine—but vaccination remains vital. Science Aug. 26, 2021.
9 Muecksch F et al. Affinity maturation of SARS-CoV-2 neutralizing antibodies confers potency, breadth, and resilience to viral escape mutations. Immunity Aug. 10 2021; 54(8): 1853-1868.
10 Wang Z et al. Naturally enhanced neutralizing breadth against SARS-CoV-2 one year after infection. Nature June 14, 2021; 595, 426–431.