Change in the Clinical Picture of Hospitalized Patients with COVID-19 between the Early and Late Period of Dominance of the Omicron SARS-CoV-2 Variant

Abstract

This study aimed to compare the clinical picture of COVID-19 in the initial and later period of Omicron dominance and to identify populations still at risk. A retrospective comparison of the clinical data of 965 patients hospitalized during the early period of Omicron’s dominance (EO, January–June 2022) with 897 patients from a later period (LO, July 2022–April 2023) from the SARSTer database was performed. Patients hospitalized during LO, compared to EO, were older, had a better clinical condition on admission, had a lower need for oxygen and mechanical ventilation, had less frequent lung involvement in imaging, and showed much faster clinical improvement. Moreover, the overall mortality during EO was 14%, higher than that in LO—9%. Despite the milder course of the disease, mortality exceeding 15% was similar in both groups among patients with lung involvement. The accumulation of risk factors such as an age of 60+, comorbidities, lung involvement, and oxygen saturation <90% resulted in a constant need for oxygen in 98% of patients, an 8% risk of mechanical ventilation, and a 30% mortality rate in the LO period. Multiple logistic regression revealed lower odds of death during the LO phase. Despite the milder course of infections caused by the currently dominant subvariants, COVID-19 prophylaxis is necessary in people over 60 years of age, especially those with comorbidities, and in the case of pneumonia and respiratory failure.

Key Considerations during the Transition from the Acute Phase of the COVID-19 Pandemic: A Narrative Review

“…Epidemiological analyses of various human populations confirmed that Omicron infections are characterized by decreased lower respiratory tract involvement, reduced odds of hospitalization due to severe COVID-19, and less mortality [74][75][76][77][78]. Despite the emergence of subsequent Omicron sublineages, such as BA.4/BA.5 and XBB, the hospitalization and death risk remained lower compared to previous SARS-CoV-2 variants, such as Delta [79][80][81][82].…”

Trends of Hepatitis A Virus Infection in Poland: Assessing the Potential Impact of the COVID-19 Pandemic and War in Ukraine

“…To assess the burden of newly diagnosed HAV cases during the COVID-19 pandemic, we explored the pre-pandemic period, depending on the dominant variants of SARS-CoV-2 [ 19 , 20 , 21 ]. The pandemic period was divided into four periods: (i) the pre-Delta lineage period from March 2020 to June 2021, (ii) the Delta lineage dominance period from July 2021 to December 2021, (iii) the early phase of the Omicron SARS-CoV-2 lineage dominance from January 2022 to June 2022 (dominated by the BA.1 and BA.2 Omicron subvariants), and (iv) a later phase of Omicron SARS-CoV-2 dominance from July 2022 to December 2023 (characterized predominantly by the dominance of XBB and its descendent sublineage).…”

The Course of COVID-19 and Long COVID: Identifying Risk Factors among Patients Suffering from the Disease before and during the Omicron-Dominant Period

“…However, the actual number of infections and deaths associated with Omicron may be even higher. Possible reasons for this include the underdiagnosis of affected individuals and the failure to report new cases of the disease due to the WHO’s announcement that COVID-19 no longer constitutes a public health emergency of international concern [ 16 ].…”