Department of Infection Control and Preparedness, Norwegian Institute of Public Health, Oslo, Norway.
Department of Infection Control and Vaccines, Norwegian Institute of Public Health, Oslo, Norway.
PLoS One. 2021 Oct 11;16(10):e0258513. doi: 10.1371/journal.pone.0258513. eCollection 2021.
Since their emergence, SARS-CoV-2 variants of concern (VOC) B.1.1.7 and B.1.351 have spread worldwide. We estimated the risk of hospitalisation and admission to an intensive care unit (ICU) for infections with B.1.1.7 and B.1.351 in Norway, compared to infections with non-VOC.
Using linked individual-level data from national registries, we conducted a cohort study on laboratory-confirmed cases of SARS-CoV-2 in Norway diagnosed between 28 December 2020 and 2 May 2021. Variants were identified based on whole genome sequencing, partial sequencing by Sanger sequencing or PCR screening for selected targets. The outcome was hospitalisation or ICU admission. We calculated adjusted risk ratios (aRR) with 95% confidence intervals (CIs) using multivariable binomial regression to examine the association between SARS-CoV-2 variants B.1.1.7 and B.1.351 with i) hospital admission and ii) ICU admission compared to non-VOC.
We included 23,169 cases of B.1.1.7, 548 B.1.351 and 4,584 non-VOC. Overall, 1,017 cases were hospitalised (3.6%) and 206 admitted to ICU (0.7%). B.1.1.7 was associated with a 1.9-fold increased risk of hospitalisation (aRR 95%CI 1.6-2.3) and a 1.8-fold increased risk of ICU admission (aRR 95%CI 1.2-2.8) compared to non-VOC. Among hospitalised cases, no difference was found in the risk of ICU admission between B.1.1.7 and non-VOC. B.1.351 was associated with a 2.4-fold increased risk of hospitalisation (aRR 95%CI 1.7-3.3) and a 2.7-fold increased risk of ICU admission (aRR 95%CI 1.2-6.5) compared to non-VOC.
Our findings add to the growing evidence of a higher risk of severe disease among persons infected with B.1.1.7 or B.1.351. This highlights the importance of prevention and control measures to reduce transmission of these VOC in society, particularly ongoing vaccination programmes, and preparedness plans for hospital surge capacity.
自出现以来，SARS-CoV-2 的关注变体（VOC）B.1.1.7 和 B.1.351 已在全球范围内传播。我们估计了挪威感染 B.1.1.7 和 B.1.351 与感染非 VOC 相比，住院和入住重症监护病房（ICU）的风险。
利用国家登记处的个体水平关联数据，我们对 2020 年 12 月 28 日至 2021 年 5 月 2 日期间在挪威确诊的 SARS-CoV-2 实验室确诊病例进行了队列研究。根据全基因组测序、Sanger 测序的部分测序或针对选定靶标的 PCR 筛选来确定变体。结果是住院或 ICU 入院。我们使用多变量二项式回归计算调整后的风险比（aRR）和 95%置信区间（CI），以检查 SARS-CoV-2 变体 B.1.1.7 和 B.1.351 与 i）住院和 ii）与非 VOC 相比，ICU 入院的关联。
我们纳入了 23169 例 B.1.1.7、548 例 B.1.351 和 4584 例非 VOC。总体而言，有 1017 例住院（3.6%），206 例入住 ICU（0.7%）。与非 VOC 相比，B.1.1.7 与住院风险增加 1.9 倍（aRR 95%CI 1.6-2.3）和 ICU 入院风险增加 1.8 倍（aRR 95%CI 1.2-2.8）相关。在住院病例中，B.1.1.7 和非 VOC 之间 ICU 入院风险无差异。与非 VOC 相比，B.1.351 与住院风险增加 2.4 倍（aRR 95%CI 1.7-3.3）和 ICU 入院风险增加 2.7 倍（aRR 95%CI 1.2-6.5）相关。
我们的研究结果增加了越来越多的证据，表明感染 B.1.1.7 或 B.1.351 的人患严重疾病的风险更高。这突显了在社会中减少这些 VOC 传播的预防和控制措施的重要性，特别是持续的疫苗接种计划和医院容量扩充的准备计划。
