Comparison of Patients Infected With Delta Versus Omicron COVID-19 Variants Presenting to Paris Emergency Departments

Donia Bouzid (1, 2) , Benoit Visseaux (1, 2) , Christian Kassasseya (3) , Asma Daoud (4) , Florent Fémy (5, 6, 7) , Christelle Hermand (8) , Jennifer Truchot (9, 6) , Sebastien Beaune (10, 11) , Nicolas Javaud (12, 13, 6) , Olivier Peyrony (14) , Anthony Chauvin (15, 6) , Prabakar Vaittinada Ayar (16) , Arthur Bourg (17) , Bruno Riou (18, 19) , Stephane Marot (19) , Ben Bloom (20) , Marine Cachanado (21, 8) , Tabassome Simon (21, 8) , Yonathan Freund (19)

1 AP-HP - Hôpital Bichat - Claude Bernard [Paris]
2 IAME (UMR_S_1137 / U1137) - Infection, Anti-microbiens, Modélisation, Evolution
3 Hôpital Henri Mondor
4 Hôpital Avicenne [AP-HP]
5 HEGP - Hôpital Européen Georges Pompidou [APHP]
6 UPCité - Université Paris Cité
7 IRBA - Institut de Recherche Biomédicale des Armées [Brétigny-sur-Orge]
8 CHU Saint-Antoine [AP-HP]
9 Hôpital Cochin [AP-HP]
10 Hôpital Ambroise Paré [AP-HP]
11 UVSQ Santé - Université de Versailles Saint-Quentin-en-Yvelines - UFR Sciences de la santé Simone Veil
12 Hôpital Louis Mourier - AP-HP [Colombes]
13 CREAK - Centre de référence national des angiœdèmes
14 AP-HP - Hopital Saint-Louis [AP-HP]
15 Hôpital Lariboisière-Fernand-Widal [APHP]
16 Hôpital Beaujon [AP-HP]
17 CHU Tenon [AP-HP]
18 ICAN - Unité de Recherche sur les Maladies Cardiovasculaires, du Métabolisme et de la Nutrition = Research Unit on Cardiovascular and Metabolic Diseases
19 CHU Pitié-Salpêtrière [AP-HP]
20 Royal London Hospital
21 CIC Paris-Est - Centre d'investigation clinique Paris Est [CHU Pitié Salpêtrière]

Background: At the end of 2021, the B.1.1.529 SARS-CoV-2 variant (Omicron) wave superseded the B.1.617.2 variant (Delta) wave. Objective: To compare baseline characteristics and in-hospital outcomes of patients with SARS-CoV-2 infection with the Delta variant versus the Omicron variant in the emergency department (ED). Design: Retrospective chart reviews. Setting: 13 adult EDs in academic hospitals in the Paris area from 29 November 2021 to 10 January 2022. Patients: Patients with a positive reverse transcriptase polymerase chain reaction (RT-PCR) test result for SARS-CoV-2 and variant identification. Measurements: Main outcome measures were baseline clinical and biological characteristics at ED presentation, intensive care unit (ICU) admission, mechanical ventilation, and in-hospital mortality. Results: A total of 3728 patients had a positive RT-PCR test result for SARS-CoV-2 during the study period; 1716 patients who had a variant determination (818 Delta and 898 Omicron) were included. Median age was 58 years, and 49% were women. Patients infected with the Omicron variant were younger (54 vs. 62 years; difference, 8.0 years [95% CI, 4.6 to 11.4 years]), had a lower rate of obesity (8.0% vs. 12.5%; difference, 4.5 percentage points [CI, 1.5 to 7.5 percentage points]), were more vaccinated (65% vs. 39% for 1 dose and 22% vs. 11% for 3 doses), had a lower rate of dyspnea (26% vs. 50%; difference, 23.6 percentage points [CI, 19.0 to 28.2 percentage points]), and had a higher rate of discharge home from the ED (59% vs. 37%; difference, 21.9 percentage points [-26.5 to -17.1 percentage points]). Compared with Delta, Omicron infection was independently associated with a lower risk for ICU admission (adjusted difference, 11.4 percentage points [CI, 8.4 to 14.4 percentage points]), mechanical ventilation (adjusted difference, 3.6 percentage points [CI, 1.7 to 5.6 percentage points]), and in-hospital mortality (adjusted difference, 4.2 percentage points [CI, 2.0 to 6.5 percentage points]). Limitation: Patients with COVID-19 illness and no SARS-CoV-2 variant determination in the ED were excluded. Conclusion: Compared with the Delta variant, infection with the Omicron variant in patients in the ED had different clinical and biological patterns and was associated with better in-hospital outcomes, including higher survival.

Domaines: Sciences du Vivant [q-bio]

Donia Bouzid, Benoit Visseaux, Christian Kassasseya, Asma Daoud, Florent Fémy, et al.. Comparison of Patients Infected With Delta Versus Omicron COVID-19 Variants Presenting to Paris Emergency Departments. Annals of Internal Medicine, 2022, 175 (6), pp.831-837. ⟨10.7326/M22-0308⟩. ⟨hal-03615584⟩