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Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis
OBJECTIVES: To compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages. METHODS: We searched the WHO COVID-19 Research database for studies that compared clinical outcomes for patients with Omicron variant and the Del...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BMJ Publishing Group
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10347449/ https://www.ncbi.nlm.nih.gov/pubmed/37419502 http://dx.doi.org/10.1136/bmjgh-2023-012328 |
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author | Relan, Pryanka Motaze, Nkengafac Villyen Kothari, Kavita Askie, Lisa Le Polain, Olivier Van Kerkhove, Maria D Diaz, Janet Tirupakuzhi Vijayaraghavan, Bharath Kumar |
author_facet | Relan, Pryanka Motaze, Nkengafac Villyen Kothari, Kavita Askie, Lisa Le Polain, Olivier Van Kerkhove, Maria D Diaz, Janet Tirupakuzhi Vijayaraghavan, Bharath Kumar |
author_sort | Relan, Pryanka |
collection | PubMed |
description | OBJECTIVES: To compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages. METHODS: We 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(2) index. Risk of bias was assessed using the tool developed by the Clinical Advances through Research and Information Translation team. RESULTS: Our 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. |
format | Online Article Text |
id | pubmed-10347449 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | BMJ Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-103474492023-07-15 Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis Relan, Pryanka Motaze, Nkengafac Villyen Kothari, Kavita Askie, Lisa Le Polain, Olivier Van Kerkhove, Maria D Diaz, Janet Tirupakuzhi Vijayaraghavan, Bharath Kumar BMJ Glob Health Original Research OBJECTIVES: To compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages. METHODS: We 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(2) index. Risk of bias was assessed using the tool developed by the Clinical Advances through Research and Information Translation team. RESULTS: Our 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. BMJ Publishing Group 2023-07-07 /pmc/articles/PMC10347449/ /pubmed/37419502 http://dx.doi.org/10.1136/bmjgh-2023-012328 Text en © World Health Organization 2023. Licensee BMJ. https://creativecommons.org/licenses/by/3.0/igo/This is an open access article distributed under the terms of the Creative Commons Attribution IGO License (CC BY 3.0 IGO (https://creativecommons.org/licenses/by/3.0/igo/) ), which permits use, distribution,and reproduction in any medium, provided the original work is properly cited. In any reproduction of this article there should not be any suggestion that WHO or this article endorse any specific organization or products. The use of the WHO logo is not permitted. This notice should be preserved along with the article’s original URL. |
spellingShingle | Original Research Relan, Pryanka Motaze, Nkengafac Villyen Kothari, Kavita Askie, Lisa Le Polain, Olivier Van Kerkhove, Maria D Diaz, Janet Tirupakuzhi Vijayaraghavan, Bharath Kumar Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title | Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title_full | Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title_fullStr | Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title_full_unstemmed | Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title_short | Severity and outcomes of Omicron variant of SARS-CoV-2 compared to Delta variant and severity of Omicron sublineages: a systematic review and metanalysis |
title_sort | severity and outcomes of omicron variant of sars-cov-2 compared to delta variant and severity of omicron sublineages: a systematic review and metanalysis |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10347449/ https://www.ncbi.nlm.nih.gov/pubmed/37419502 http://dx.doi.org/10.1136/bmjgh-2023-012328 |
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