Comparison of Omicron and Delta Variants of SARS-CoV-2: A SystematicReview of Current Evidence
Bibliographic record
Abstract
INTRODUCTION: Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) caused the outbreak of coronavirus disease 2019 (COVID-19) in late 2019 in Wuhan, China. In early 2020, the disease spread rapidly around the world. Since the pandemic, SARS-CoV-2 has evolved dramatically into a wide variety of variants endowed with devastating properties. As of March 6, 2022, five SARS-CoV-2 variants of concern, including Alpha, Beta, Gamma, Delta, and Omicron strains have been identified. Due to the crucial importance of understanding the differences between the Omicron and Delta variants, this systematic review was conducted. METHODS: This systematic review investigated new variants of Omicron SARS-CoV-2 based on current studies. Online databases were searched for English articles as of January 03, 2023. Selection of publications was a two-step process of title/abstract and full-text assessment against eligibility criteria. The relevant data from the included articles were systematically collected and organized in a designed table for analysis. To ensure the quality of the review, the PRISMA checklist and Newcastle- Ottawa Scale (NOS) of quality assessment were utilized. RESULTS: The data extracted from 58 articles were analyzed, including 10003 pieces of evidence. Lower risk of hospitalization, ICU admission, and mortality after vaccination were reported in the Omicron variant compared to the Delta variant. Additionally, the Delta variant led to more severe clinical symptoms in comparison to the Omicron variant. CONCLUSION: The Omicron variant of SARS-CoV-2 results in less severe disease outcomes as compared to Delta. Nevertheless, it remains crucial to maintain ongoing monitoring, implement containment measures, and adapt vaccination protocols to effectively address the evolving variants.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.008 | 0.043 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.008 | 0.008 |
| Bibliometrics | 0.015 | 0.013 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".