Variability in the Clinical Course of COVID-19 in a Retrospective Analysis of a Large Real-World Database.

The COVID-19 pandemic proceeds in waves, with variable characteristics of the clinical picture resulting from the evolution of the SARS-CoV-2 virus. This study aimed to compare the epidemiological characteristics, symptomatology, and outcomes of the disease in patients hospitalized for COVID-19 during periods of different variants dominance. Comparing the periods of dominance of variants preceding the Delta variant, the Delta period was characterized by a higher share of hospitalized females, less frequent comorbidities among patients, and a different age distribution. The lowest need for oxygen therapy and mechanical ventilation was observed under Omicron dominance. The triad of classic COVID-19 symptoms, cough, fever, dyspnoea, and fatigue, were most prevalent during the Delta period, and significantly less common under the Omicron dominance. During the Omicron period, nearly twice as many patients as in the previous periods could be discharged from the hospital within 7 days; the overall 28-day mortality was significantly lower compared to that of the Delta period. It also did not differ between periods that were dominated by the BA.1 and BA.2 subvariants. The study indicates that the Omicron SARS-CoV-2 variant that dominated between January and June 2022 caused a disease which resembled the common cold, and was caused by seasonal alpha and beta-coronaviruses with a low pathogenicity for humans. However, one should note that this effect may not only have been related to biological features of the Omicron lineage, but may additionally have been driven by the increased levels of immunization through natural infections and vaccinations, for which we could not account for due to a lack of sufficient data.

Differences between the course of SARS-CoV-2 infections in the periods of the Delta and Omicron variant dominance in Poland.

INTRODUCTION: Up to now, COVID­19 caused more than 6 million deaths worldwide. So far, 5 variants of concerns have been identified, with Delta and Omicron being the subject of our analysis. OBJECTIVES: We aimed to compare baseline characteristics and outcomes of patients hospitalized during the Delta and Omicron predominance in Poland. PATIENTS AND METHODS: The study population consisted of 2225 patients divided into 2 groups depending on the variant with which they were infected during the corresponding period of the pandemic. RESULTS: During the Delta wave, the median age of patients was significantly lower (65 vs 73 years; P <0.001), and the cohort was significantly less burdened with comorbidities than during the Omicron surge. The Omicron­infected patients presented significantly less often in an unstable symptomatic state with SpO2 equal to or below 90% on admission (49.9% for Delta vs 29.9% for Omicron; P <0.001). Regardless of the pandemic period, the 2 most common early symptoms of COVID­19 were fever and cough. In­hospital treatment consisted of antiviral drugs, more frequently used in the Omicron wave, and immunomodulatory drugs, more frequently used during the Delta wave. The risk of mechanical ventilation was significantly lower in the patients infected with the Omicron variant (7.2% for Delta vs 3.1% for Omicron; P <0.001). For the age group above 80 years old, the risk of death was significantly higher during the Delta wave than during the Omicron wave. The risk of death was significantly lower in the patients treated with antiviral drugs regardless of the pandemic wave. CONCLUSIONS: The Delta variant is associated with a more severe clinical course of the disease and a higher risk of death than the Omicron variant.

Real-world experience with molnupiravir during the period of SARS-CoV-2 Omicron variant dominance.

BACKGROUND: The real-world effectiveness of molnupiravir (MOL) during the dominance of Omicron SARS-CoV-2 lineage is urgently needed since the available data relate to the period of circulation of other viral variants. Therefore, this study assessed the efficacy of MOL in patients hospitalized for COVID-19 in a real-world clinical practice during the wave of Omicron infections. METHODS: Among 11,822 patients hospitalized after 1 March 2020 and included in the SARSTer national database, 590 were treated between 1 January and 30 April 2022, a period of dominance of the Omicron SARS-CoV-2 variant. MOL was administered to 203 patients, whereas 387 did not receive any antiviral regimen. Both groups were similar in terms of sex, BMI and age allowing for direct comparisons. RESULTS: Patients who did not receive antiviral therapy significantly more often required the use of Dexamethasone and Baricitinib. Treatment with MOL resulted in a statistically significant reduction in mortality during the 28-day follow-up (9.9 vs. 16.3%), which was particularly evident in the population of patients over 80 years of age treated in the first 5 days of the disease (14.6 vs. 35.2%). MOL therapy did not affect the frequency of the need for mechanical ventilation, but patients treated with MOL required oxygen supplementation less frequently than those without antivirals (31.7 vs. 49.2%). The time of hospitalization did not differ between groups. CONCLUSIONS: The use of molnupiravir in patients hospitalized for COVID-19 during the dominance of Omicron variant reduced mortality. This effect is particularly evident in patients over 80 years of age.