According to an Israeli study, natural immunity is 27 times stronger than that induced by COVID vaccines.at 29.12.2021
A group of ten Israeli researchers conducted the world's most extensive study (which is still in preprint and being peer-reviewed) comparing natural immunity to artificially induced immunity from Pfizer-produced COVID vaccines. According to their findings, natural immunity is 27 times more effective than vaccine-induced immunity.
The ten researchers, all of whom work at prestigious Israeli medical institutions, hypothesized that natural immunity is likely to be stronger than that conferred by the vaccine. And that's because Israel, one of the first countries to launch a national vaccination campaign, saw an unprecedented increase   in COVID cases following vaccination. This situation has raised questions about the Delta vaccine's efficacy. Furthermore, scientific studies  have found only minor differences in the short-term effectiveness of the vaccine in dealing with the Delta variant between vaccinated and unvaccinated individuals.
These are the motivations that prompted the ten researchers to start the study , especially since there is currently enough data to make a relevant assessment. It has been a long time since both the pandemic's start and the vaccine's implementation permit the investigation of the long-term protection of natural immunity versus vaccine-induced immunity. The study, published on August 25 of this year, used data from the Maccabi Healthcare Services (MHS) database, Israel's second-largest healthcare institution, to track the evolution of 673,676 people over the age of 16 who were fully vaccinated; 62,883 unvaccinated people who went through the disease; and 42,099 people who went through the illness but only received a single dose of the Pfizer vaccine.
The researchers assessed the subjects' progression using three statistical models and four criteria: SARS-CoV-2 infection or reinfection, a symptomatic manifestation of the disease, hospitalization, and death. The tracking period was between June 1 and August 14, 2021, when the Delta variant was dominant in Israel.
According to the Israeli researchers' findings, those vaccinated with both doses had 13.06 times higher risk (95 % CI, 8.08-21.11) of infection with the Delta variant than those who were not vaccinated and previously had the disease. In addition, compared to the other two groups, those who received both doses of the vaccine had a significantly higher risk of developing the symptomatic form of the disease. The vaccinated subjects had a higher risk of hospitalization than those who had acquired natural immunity through a previous infection.
According to the results, during the follow-up period, 257 cases of coronavirus infection were recorded, 238 of which occurred in the group of the subjects vaccinated with both doses and 19 cases in the group of those who had the disease. Regarding the symptomatic disease manifestation, the researchers registered 191 cases in the vaccinated group and eight patients in the unvaccinated group out of 199 reported cases. In terms of hospitalizations, nine were recorded, with eight from the vaccinated group and one from the unvaccinated group.
Thus, the study's findings indicate that natural immunity provides even longer-lasting protection against infection, symptomatic disease, and hospitalization caused by the Delta variant of SARS-CoV-2 than immunity induced by Pfizer's two-dose vaccination.
Professor Martin Kulldorff, an eminent biostatistician and epidemiologist at Harvard Medical School who designed the CDC vaccine evaluation system, commented on the study's findings, saying that this information proves that vaccination passports are unscientific and discriminatory. "Passing through COVID provides better immunity than vaccines, so vaccination passports are more discriminatory and unethical than scientific nonsense."  The Harvard professor says that this isn't the only study that shows natural immunity provides "immense protection" against COVID. Still, there have been 15 academic studies that back up the findings of Israeli researchers.
 Kahn Sagol Maccabi (KSM) Research & Innovation Center, Maccabi Healthcare Services, Tel Aviv, 68125, Israel; Maccabitech Institute for Research and Innovation, Maccabi Healthcare Services, Israel; Internal Medicine COVID-19 Ward, Samson Assuta Ashdod University Hospital, Ashdod Israel; Sackler Faculty of Medicine, School of Public Health, Tel Aviv University, Tel Aviv, Israel.
COVID-19 in Israel dashboard. 2021
 Decline in Vaccine Effectiveness Against Infection and Symptomatic Illness [Internet]. [cited 2021 Jul 22]. Available from: https://www.gov.il/en/Departments/news/05072021-03
Bernal JL, Andrews N, Gower C, et al. Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. https://doi.org/101056/NEJMoa2108891 [Internet] 2021 [cited 2021 Jul 22];NEJMoa2108891. Available from: https://www.nejm.org/doi/full/10.1056/NEJMoa2108891