Background This meta-analysis aims to assess the effectiveness of the current Sars-Cov2
vaccine regimens against Omicron infection. A secondary endpoint aims to investigate the …

Background COVID-19 is a respiratory illness caused by SARS-CoV-2. The most recent
variant is Omicron (line B. 1.1. 529), which was first identified in South Africa in November …

Background A rapidly growing body was observed of literature evaluating the vaccine
effectiveness (VE) against Omicron in test-negative design studies. Methods We …

Background The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron
variant is currently the dominant variant globally. This third interim analysis of a living …

Real-world data on the effectiveness of COVID-19 vaccines against the Omicron variant (B.
1.1. 529) is limited. This systematic review aimed to investigate the real-world effectiveness …

Despite widespread mass rollout programs, the rapid spread of the SARS-CoV-2 Omicron
variant called into question the effectiveness of the existing vaccines against infection …

Vaccine effectiveness (VE) and the urgency of booster vaccination against SARS-CoV-2
Omicron variant need evaluation. A systematic search was conducted from 1–6 April, 2022 …

Background The global surge in the omicron (B. 1.1. 529) variant has resulted in many
individuals with hybrid immunity (immunity developed through a combination of SARS-CoV …

Objectives: To compare the effectiveness of a primary COVID-19 vaccine series plus a
booster dose with a primary series alone for the prevention of Omicron variant COVID-19 …

Vaccine effectiveness is lower and wanes faster against infection and symptomatic disease
caused by the omicron variant of SARS-CoV-2 than was observed with previous variants …