Evidence map›Paper›PMID 37419502›Full record

SynthesisBMJ global health2023

Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis.

Pryanka Relan, Nkengafac Villyen Motaze, Kavita Kothari, Lisa Askie, Olivier Le Polain, Maria D Van Kerkhove, Janet Diaz, Bharath Kumar Tirupakuzhi Vijayaraghavan

Abstract readSystematic ReviewMeta-Analysis
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in BMJ global health, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 72 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
72citing papers in PubMed, 5 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

72 citing papers in PubMed, 5 syntheses or guidelines pooled it.

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12 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

8 authors.

Pryanka Relan *Health Emergencies Programme, WHO, Geneva, Switzerland bharathkumartv@gmail.com relanp@who.int.ORCID 0000-0002-9543-7891
Nkengafac Villyen MotazeHealth Emergencies Programme, WHO, Geneva, Switzerland.
Kavita KothariLibrary and Digital Information Networks, World Health Organization, Kobe, Japan.
Lisa AskieMethods and Standards Unit, Science Division, World Health Organization, Geneva, Switzerland.
Olivier Le PolainAcute Response Coordination Department, World Health Organization, Geneva, Switzerland.
Maria D Van KerkhoveCOVID-19 Health Operations, World Health Emergencies Programme, World Health Organization, Geneva, Switzerland.
Janet DiazHealth Emergencies Programme, WHO, Geneva, Switzerland.
Bharath Kumar Tirupakuzhi Vijayaraghavan *Critical Care, Apollo Hospitals, Chennai, Tamil Nadu, India bharathkumartv@gmail.com relanp@who.int.ORCID 0000-0002-1801-0667

Funding

World Health Organization 001
6 · The paper itself

Abstract

objectivesTo compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages.

methodsWe searched the WHO COVID-19 Research database for studies that compared clinical outcomes for patients with Omicron variant and the Delta variant, and separately Omicron sublineages BA.1 and BA.2. A random-effects meta-analysis was used to pool estimates of relative risk (RR) between variants and sublineages. Heterogeneity between studies was assessed using the I

resultsOur search identified 1494 studies and 42 met the inclusion criteria. Eleven studies were published as preprints. Of the 42 studies, 29 adjusted for vaccination status; 12 had no adjustment; and for 1, the adjustment was unclear. Three of the included studies compared the sublineages of Omicron BA.1 versus BA.2. As compared with Delta, individuals infected with Omicron had 61% lower risk of death (RR 0.39, 95% CI 0.33 to 0.46) and 56% lower risk of hospitalisation (RR 0.44, 95% CI 0.34 to 0.56). Omicron was similarly associated with lower risk of intensive care unit (ICU) admission, oxygen therapy, and non-invasive and invasive ventilation. The pooled risk ratio for the outcome of hospitalisation when comparing sublineages BA.1 versus BA.2 was 0.55 (95% 0.23 to 1.30). DISCUSSION: Omicron variant was associated with lower risk of hospitalisation, ICU admission, oxygen therapy, ventilation and death as compared with Delta. There was no difference in the risk of hospitalisation between Omicron sublineages BA.1 and BA.2. PROSPERO REGISTRATION NUMBER: CRD42022310880.

Indexed as

COVID-19SARS-CoV-2Databases, FactualHumansOxygenOxygenCOVID-19Critical IllnessSARS-CoV-2

Identifiers

PMID37419502
PMCPMC10347449

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.