TY - JOUR T1 - Clinical Severity of SARS-CoV-2 Omicron Variant Compared with Delta among Hospitalized COVID-19 Patients in Belgium during Autumn and Winter Season 2021-2022. JF - Viruses Y1 - 2022 A1 - Nina Van Goethem A1 - Pui Yan Jenny Chung A1 - Marjan Meurisse A1 - Mathil Vandromme A1 - Laurane De Mot A1 - Ruben Brondeel A1 - Veerle Stouten A1 - Sofieke Klamer A1 - Lize Cuypers A1 - Toon Braeye A1 - Lucy Catteau A1 - Louis Nevejan A1 - Joris Van Loenhout A1 - Koen Blot KW - ADOLESCENT KW - Belgium KW - Cohort Studies KW - COVID-19 KW - Humans KW - Retrospective Studies KW - SARS-CoV-2 KW - Seasons AB -

This retrospective multi-center matched cohort study assessed the risk for severe COVID-19 (combination of severity indicators), intensive care unit (ICU) admission, and in-hospital mortality in hospitalized patients when infected with the Omicron variant compared to when infected with the Delta variant. The study is based on a causal framework using individually-linked data from national COVID-19 registries. The study population consisted of 954 COVID-19 patients (of which, 445 were infected with Omicron) above 18 years old admitted to a Belgian hospital during the autumn and winter season 2021-2022, and with available viral genomic data. Patients were matched based on the hospital, whereas other possible confounders (demographics, comorbidities, vaccination status, socio-economic status, and ICU occupancy) were adjusted for by using a multivariable logistic regression analysis. The estimated standardized risk for severe COVID-19 and ICU admission in hospitalized patients was significantly lower (RR = 0.63; 95% CI (0.30; 0.97) and RR = 0.56; 95% CI (0.14; 0.99), respectively) when infected with the Omicron variant, whereas in-hospital mortality was not significantly different according to the SARS-CoV-2 variant (RR = 0.78, 95% CI (0.28-1.29)). This study demonstrates the added value of integrated genomic and clinical surveillance to recognize the multifactorial nature of COVID-19 pathogenesis.

VL - 14 CP - 6 M3 - 10.3390/v14061297 ER -