Abstract The coronavirus disease 2019 (COVID‐19) pandemic can hardly end with the
emergence of different variants over time. In the past 2 years, several variants of severe …

Abstract The SARS-CoV-2 Omicron variant has demonstrated enhanced transmissibility and
escape of vaccine-derived immunity. Although first-generation vaccines remain effective …

Background The two inactivated SARS-CoV-2 vaccines, CoronaVac and BBIBP-CorV, have
been widely used to control the COVID-19 pandemic. The influence of multiple factors on …

Objective To estimate the effectiveness of a two dose vaccine schedule (mRNA-1273,
BNT162b2, and BBIBP-CorV) against SARS-CoV-2 infection and covid-19 related death and …

Abstract Background The SARS-CoV-2 Omicron BA. 2 subvariant replaced BA. 1 globally in
early 2022, and caused an unprecedented tsunami of cases in Hong Kong, resulting in the …

Background Omicron (B. 1.1. 529), a variant of SARS-CoV-2, has emerged as a dominant
strain in COVID-19 pandemic. This development has raised concerns about the …

Background: The efficacy of the BNT162b2 vaccine in pediatrics was assessed by
randomized trials before the Omicron variant's emergence. The long-term durability of …

Background Increased pediatric COVID-19 occurrence due to the SARS-CoV-2 Omicron
variant has raised concerns about the effectiveness of existing vaccines. The protection …

Background The impact of pre-infection vaccination on the risk of long COVID remains
unclear in the pediatric population. We aim to assess the effectiveness of BNT162b2 on long …

We aimed to evaluate the effectiveness or efficacy of heterologous or homologous COVID-
19 vaccine regimens against COVID-19-related outcomes after primary immunization with …