Health Emergencies Programme, WHO, Geneva, Switzerland
Health Emergencies Programme, WHO, Geneva, Switzerland.
BMJ Glob Health. 2023 Jul;8(7). doi: 10.1136/bmjgh-2023-012328.
To compare severity and clinical outcomes from Omicron as compared with the Delta variant and to compare outcomes between Omicron sublineages.
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 index. Risk of bias was assessed using the tool developed by the Clinical Advances through Research and Information Translation team.
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).
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.
CRD42022310880.
比较奥密克戎变异株与德尔塔变异株的严重程度和临床结局，并比较奥密克戎亚系之间的结局。
我们在世界卫生组织 COVID-19 研究数据库中检索了比较奥密克戎变异株和德尔塔变异株以及奥密克戎亚系 BA.1 和 BA.2 患者临床结局的研究。使用随机效应荟萃分析汇总变异株和亚系之间相对风险（RR）的估计值。使用临床进展通过研究和信息转化团队开发的工具评估研究之间的异质性。
我们的搜索确定了 1494 项研究，其中 42 项符合纳入标准。其中 11 项研究作为预印本发表。在这 42 项研究中，29 项调整了疫苗接种状态；12 项没有调整；对于 1 项，调整情况不清楚。其中 3 项研究比较了奥密克戎 BA.1 与 BA.2 亚系。与德尔塔相比，感染奥密克戎的个体死亡风险降低 61%（RR 0.39，95%CI 0.33 至 0.46），住院风险降低 56%（RR 0.44，95%CI 0.34 至 0.56）。奥密克戎与 ICU 入院、氧疗、无创和有创通气的风险降低也具有类似相关性。比较亚系 BA.1 与 BA.2 时，住院结局的汇总风险比为 0.55（95%CI 0.23 至 1.30）。
与德尔塔相比，奥密克戎变异株与住院、ICU 入院、氧疗、通气和死亡风险降低相关。奥密克戎亚系 BA.1 和 BA.2 之间的住院风险无差异。
CRD42022310880。
