Background The safety and immunogenicity of the bivalent omicron-containing mRNA-
1273.214 booster vaccine are not known. Methods In this ongoing, phase 2–3 study, we …

Background Synthesising evidence on the long-term vaccine effectiveness of COVID-19
vaccines (BNT162b2 [Pfizer–BioNTech], mRNA-1273 [Moderna], ChAdOx1 nCoV-19 …

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 …

The latest SARS-CoV-2 variant of concern Omicron, with its immune escape from
therapeutic anti-Spike monoclonal antibodies and WA-1 vaccine-elicited sera, demonstrates …

Background We aimed to systematically review the magnitude and duration of the protective
effectiveness of prior infection (PE) and hybrid immunity (HE) against Omicron infection and …

Several severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron
subvariants have recently emerged, becoming the dominant circulating strains in many …

This study estimates the effectiveness of previous infection with SARS-CoV-2 in preventing
reinfection with Omicron BA. 4/BA. 5 subvariants using a test-negative, case–control study …

Globally, during the week of 11 to 17 July 2022, the number of weekly cases plateaued, with
just under 6.3 million new cases after an increasing trend for the past five weeks (Figure 1) …

Background Hybrid immunity (a combination of natural and vaccine-induced immunity)
provides additional immune protection against the coronavirus disease 2019 (COVID-19) …

Abstract Background Studies comparing SARS-CoV-2 reinfection outcomes among
individuals with previous infection (natural immunity) and previous infection plus vaccination …