Breakthrough infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-
2) in fully vaccinated individuals are receiving intense scrutiny because of their importance …

Background Vaccines are critical cost-effective tools to control the coronavirus disease 2019
(COVID-19) pandemic. However, the emergence of variants of the severe acute respiratory …

The recent emergence of the SARS-CoV-2 Omicron variant is raising concerns because of
its increased transmissibility and its numerous spike mutations, which have the potential to …

Background Vaccine effectiveness against COVID-19 beyond 6 months remains
incompletely understood. We aimed to investigate the effectiveness of COVID-19 …

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new beta coronavirus
that emerged at the end of 2019 in the Hubei province of China. SARS-CoV-2 causes …

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

The delay or refusal of vaccination, which defines vaccine hesitancy, is a major challenge to
successful control of COVID-19 epidemic. The huge number of publications addressing …

With the high rate of COVID-19 infections worldwide, the emergence of SARS-CoV-2
variants was inevitable. Several mutations have been identified in the SARS-CoV-2 …

Objective The gut microbiota plays a key role in modulating host immune response. We
conducted a prospective, observational study to examine gut microbiota composition in …

Accumulating evidence shows a progressive decline in the efficacy of coronavirus disease
2019 (COVID‐19)(severe acute respiratory syndrome coronavirus 2 [SARS‐CoV‐2]) …