Clinical outcomes of the severe acute respiratory syndrome coronavirus 2 Omicron and Delta variant: systematic review and meta-analysis of 33 studies covering 6 037 144 coronavirus disease 2019-positive patients.
Clin Microbiol Infect
; 29(7): 835-844, 2023 Jul.
Article
in English
| MEDLINE | ID: covidwho-2308959
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 severity.OBJECTIVES:
To compare the clinical outcomes of COVID-19-positive patients with Omicron and Delta variant infection. DATA SOURCES Searches were implemented up to 8 November 2022 in PubMed, Web of Science, BioRvix, and MedRvix. STUDY ELIGIBILITY CRITERIA Eligible studies were cohort studies reporting the clinical outcomes of COVID-19-positive patients with Omicron and Delta variant infection, including hospitalization, intensive care unit (ICU) admission, receiving invasive mechanical ventilation (IMV), and death.PARTICIPANTS:
COVID-19-positive patients with Omicron and Delta variant infection. ASSESSMENT OF RISK OF BIAS Risk of bias was assessed employing the Newcastle-Ottawa Scale. METHODS OF DATASYNTHESIS:
Random-effect models were employed to pool the ORs and 95% CIs to compare the risk of clinical outcome. I2 was employed to evaluate the heterogeneity between studies.RESULTS:
A total of 33 studies with 6 037 144 COVID-19-positive patients were included in this meta-analysis. In the general population of COVID-19-positive patients, compared with Delta, Omicron variant infection resulted in a decreased risk of hospitalization (10.24% vs. 4.14%, OR = 2.91, 95% CI = 2.35-3.60), ICU admission (3.67% vs. 0.48%, OR = 3.64, 95% CI = 2.63-5.04), receiving IMV (3.93% vs. 0.34%, OR = 3.11, 95% CI = 1.76-5.50), and death (2.40% vs. 0.46%, OR = 2.97, 95% CI = 2.17-4.08). In the hospitalized patients with COVID-19, compared with Delta, Omicron variant infection resulted in a decreased risk of ICU admission (20.70% vs. 12.90%, OR = 1.63, 95% CI = 1.32-2.02), receiving IMV (10.90% vs. 5.80%, OR = 1.65, 95% CI = 1.28-2.14), and death (10.72% vs. 7.10%, OR = 1.44, 95% CI = 1.22-1.71).CONCLUSIONS:
Compared with Delta, the severity of Omicron variant infection decreased.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
/
Randomized controlled trials
/
Reviews
/
Systematic review/Meta Analysis
Topics:
Variants
Limits:
Humans
Language:
English
Journal:
Clin Microbiol Infect
Journal subject:
Communicable Diseases
/
Microbiology
Year:
2023
Document Type:
Article
Affiliation country:
J.cmi.2023.03.017
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