Introduction A precise estimate of the frequency and severity of SARS‐CoV‐2 reinfections
would be critical to optimize restriction and vaccination policies for the hundreds of millions …

Since the discovery of SARS-CoV-2, changes in genotype and reinfection with different
variants have been observed in COVID-19-recovered patients, raising questions around the …

Background There is a paucity of data on vaccine-induced or infection-induced (hybrid or
natural) immunity against omicron (B. 1.1. 529) subvariant BA. 2, particularly in comparing …

Importance The Omicron variant is phylogenetically and antigenically distinct from earlier
SARS-CoV-2 variants and the original vaccine strain. Protection conferred by prior SARS …

Abstract Background The SARS-CoV-2 virus elicited a major public concern worldwide
since December 2019 due to the high number of infections and deaths caused by COVID …

The addictive protection against SARS-CoV-2 reinfection conferred by vaccination, as
compared to natural immunity alone, remains to be quantified. We thus carried out a meta …

The two nearby Amazonian cities of Iquitos and Manaus endured explosive COVID-19
epidemics and may well have suffered the world's highest infection and death rates over …

SARS-CoV-2 reinfections increased substantially after Omicron variants emerged. Large-
scale community-based comparisons across multiple Omicron waves of reinfection …

Abstract Background In December 2019, severe acute respiratory syndrome coronavirus 2
(SARS-CoV-2) emerged with a high transmissibility rate and resulted in numerous negative …

Background To date, only a few studies reported data regarding the development of
mucosal immune response after the BNT162b2-booster vaccination. Methods Samples of …