Effectiveness of COVID-19 vaccines against Omicron and Delta hospitalisation, a test negative case-control study

J Stowe, N Andrews, F Kirsebom, M Ramsay… - Nature …, 2022 - nature.com
The Omicron variant has been associated with reduced vaccine effectiveness (VE) against
mild disease with rapid waning. Meanwhile Omicron has also been associated with milder …

Effectiveness of the pre-Omicron COVID-19 vaccines against Omicron in reducing infection, hospitalization, severity, and mortality compared to Delta and other …

P Paul, A El-Naas, O Hamad, MA Salameh… - Human Vaccines & …, 2023 - Taylor & Francis
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 …

[HTML][HTML] Assessing vaccine effectiveness against severe COVID-19 disease caused by omicron variant. Report from a meeting of the World Health Organization

DR Feikin, LJ Abu-Raddad, N Andrews, MA Davies… - Vaccine, 2022 - Elsevier
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 …

COVID-19 hospitalisations in immunocompromised individuals in the Omicron era: a population-based observational study using surveillance data in British Columbia …

T Bahremand, JA Yao, C Mill, J Piszczek… - The Lancet Regional …, 2023 - thelancet.com
Background People with immune dysfunction are at higher risk of severe outcomes from
COVID-19 infection, but relatively little epidemiologic information is available for mostly …

Severity of omicron variant of concern and effectiveness of vaccine boosters against symptomatic disease in Scotland (EAVE II): a national cohort study with nested …

A Sheikh, S Kerr, M Woolhouse… - The Lancet Infectious …, 2022 - thelancet.com
Background Since its emergence in November, 2021, in southern Africa, the SARS-CoV-2
omicron variant of concern (VOC) has rapidly spread across the world. We aimed to …

[HTML][HTML] Reduction of the risk of severe COVID-19 due to Omicron compared to Delta variant in Italy (November 2021–February 2022)

D Petrone, A Mateo-Urdiales, C Sacco… - International Journal of …, 2023 - Elsevier
Abstract Objectives During 2022, Omicron became the dominant SARS-CoV-2 variant in
Europe. This study aims to assess the impact of such variant on severe disease from SARS …

Estimated effectiveness of COVID-19 vaccines against Omicron or Delta symptomatic infection and severe outcomes

SA Buchan, H Chung, KA Brown, PC Austin… - JAMA network …, 2022 - jamanetwork.com
Importance The incidence of SARS-CoV-2 infection, including among individuals who have
received 2 doses of COVID-19 vaccine, increased substantially following the emergence of …

Role of previous infection with SARS-CoV-2 in protecting against omicron reinfections and severe complications of COVID-19 compared to pre-omicron variants: A …

M Arabi, Y Al-Najjar, O Sharma, I Kamal, A Javed… - BMC Infectious …, 2023 - Springer
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 …

Assessing COVID-19 vaccine effectiveness against Omicron subvariants: Report from a meeting of the World Health Organization

DR Feikin, MM Higdon, N Andrews, S Collie, MD Knoll… - Vaccine, 2023 - Elsevier
Emerging in November 2021, the SARS-CoV-2 Omicron variant of concern exhibited
marked immune evasion resulting in reduced vaccine effectiveness against SARS-CoV-2 …

Risk of hospitalisation associated with infection with SARS-CoV-2 omicron variant versus delta variant in Denmark: an observational cohort study

P Bager, J Wohlfahrt, S Bhatt, M Stegger… - The Lancet Infectious …, 2022 - thelancet.com
Background Estimates of the severity of the SARS-CoV-2 omicron variant (B. 1.1. 529) are
crucial to assess the public health impact associated with its rapid global dissemination. We …