Natural Immunity Versus Vaccine-Induced Immunity

The Study: Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections

covid-19 vaccine

I wanted to share this interesting study. I’m sure this study will receive a lot of criticism because of the controversial findings. NOTE: This study is NOT anti vaccination per se but rather may be highlighting some early findings in the differences between how a immunity is conveyed via mRNA vaccination versus exposure to the whole virus which occurs following natural infection. 


Overview: This paper is a very straightforward, retrospective study out of Israel which compares three groups: 1) Fully vaccinated subjects with NO HISTORY of prior COVID infection, 2) previously infected individuals who had not been vaccinated, and (3)  previously infected infected individuals who had also received a single vaccine dose.                                                                                                 

Results SARS-CoV-2-naïve vaccinees had a 13.06-fold (95% CI, 8.08 to 21.11) increased risk for breakthrough infection with the Delta variant compared to those previously infected, when the first event (infection or vaccination) occurred during January and February of 2021. The increased risk was significant (P<0.001) for symptomatic disease as well. When allowing the infection to occur at any time before vaccination (from March 2020 to February 2021), evidence of waning natural immunity was demonstrated, though SARS-CoV-2 naïve vaccinees had a 5.96-fold (95% CI, 4.85 to 7.33) increased risk for breakthrough infection and a 7.13-fold (95% CI, 5.51 to 9.21) increased risk for symptomatic disease. SARS-CoV-2-naïve vaccinees were also at a greater risk for COVID-19-related-hospitalizations compared to those that were previously infected.

Conclusions 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.

Sivan Gazit, Roei Shlezinger, Galit Perez, Roni Lotan, Asaf Peretz, Amir Ben-Tov, Dani Cohen, Khitam Muhsen, Gabriel Chodick, Tal Patalon Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: reinfections versus breakthrough infections. Published in medRxiv. Preprint server for health sciences. Aug 25,2021

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