Objectives To compare severity and clinical outcomes from Omicron as compared with the
Delta variant and to compare outcomes between Omicron sublineages. Methods We …

Abstract Background Although the SARS-CoV-2 Omicron variant is considered to induce
less severe disease, there have been no consistent results on the extent of the decrease in …

Abstract SARS-CoV-2 Omicron BA. 1 and BA. 2 subvariants are genetically divergent. We
conducted a matched, test-negative, case-control study to estimate duration of protection of …

The COVID-19 pandemic caused by novel severe acute respiratory syndrome coronavirus-2
(SARS-CoV-2) is responsible for more than 500 million cases worldwide as of April 2022 …

Background To date, more than 761 million confirmed SARS-CoV-2 infections have been
recorded globally, and more than half of all children are estimated to be seropositive …

Introduction Information regarding the clinical manifestations and outcomes of coronavirus
disease 2019 (COVID-19) in children under the Omicron variant predominant period is still …

Importance Children's role in spreading virus during the COVID-19 pandemic is yet to be
elucidated, and measuring household transmission traditionally requires contact tracing …

Starting in late 2019, a novel coronavirus rapidly spread throughout the world, resulting in a
global pandemic. The virus was designated severe acute respiratory syndrome coronavirus …

Importance Bivalent mRNA COVID-19 vaccines were recommended in the US for children
and adolescents aged 12 years or older on September 1, 2022, and for children aged 5 to …

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 …