pupidup
This is the largest real-world observational study comparing natural immunity, gained
through previous SARS-CoV-2 infection, to vaccine-induced immunity, afforded by
the BNT162b2 mRNA vaccine. Our large cohort, enabled by Israel’s rapid rollout of
the mass-vaccination campaign, allowed us to investigate the risk for additional
infection – either a breakthrough infection in vaccinated individuals or reinfection in
previously infected ones – over a longer period than thus far described.
Our analysis demonstrates that SARS-CoV-2-naïve vaccinees had a 13.06-fold
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 for a symptomatic
disease as well.
Broadening the research question to examine the extent of the phenomenon, we
allowed the infection to occur at any time between March 2020 to February 2021
(when different variants were dominant in Israel), compared to vaccination only in
January and February 2021. Although the results could suggest waning natural
immunity against the Delta variant, those vaccinated are still at a 5.96-fold increased
risk for breakthrough infection and at a 7.13-fold increased risk for symptomatic
disease compared to those previously infected. SARS-CoV-2-naïve vaccinees were
also at a greater risk for COVID-19-related-hospitalization compared to those who were previously infected.

This analysis demonstrated that natural immunity affords longer lasting and stronger
protection against infection, symptomatic disease and hospitalization due to the Delta
variant of SARS-CoV-2, compared to the BNT162b2 two-dose vaccine-induced
immunity.

augusts bļe kaut kurš, 2021