Departments of Infection Control and Vaccines.
Infection Control and Preparedness.
Pediatrics. 2022 Sep 1;150(3). doi: 10.1542/peds.2022-057564.
There is limited evidence on whether the relative severity of coronavirus disease 2019 (COVID-19) in children and adolescents differs for different severe acute respiratory syndrome coronavirus 2 variants. We compare the risk of hospitalization to acute COVID-19 or multisystem inflammatory syndrome in children (MIS-C) among unvaccinated persons <18 years with COVID-19 (cases) between waves of the Alpha, Delta, and Omicron (sublineage BA.1) variants in Norway.
We used linked individual-level data from national registries to calculate adjusted risk ratios (aRR) with 95% confidence interval (CI) using multivariable log-binomial regression. We adjusted for variant wave, demographic characteristics, and underlying comorbidities.
We included 10 538 Alpha (21 hospitalized with acute COVID-19, 7 MIS-C), 42 362 Delta (28 acute COVID-19, 14 MIS-C), and 82 907 Omicron wave cases (48 acute COVID-19, 7 MIS-C). The risk of hospitalization with acute COVID-19 was lower in the Delta (aRR: 0.53, 95% CI: 0.30-0.93) and Omicron wave (aRR: 0.40, 95% CI: 0.24-0.68), compared to the Alpha wave. We found no difference in this risk for Omicron compared to Delta. The risk of MIS-C was lower for Omicron, compared to Alpha (aRR: 0.09, 95% CI: 0.03-0.27) and Delta (aRR: 0.26, 95% CI: 0.10-0.63).
We do not find clear evidence that different variants have influenced the risk of hospitalization with acute COVID-19 among unvaccinated children and adolescents in Norway. The lower risk of this outcome with Omicron and Delta may reflect changes in other factors over time, such as the testing strategy, maternal vaccination and/or hospitalization criteria. The emergence of Omicron has reduced the risk of MIS-C.
关于儿童和青少年 2019 年冠状病毒病（COVID-19）的相对严重程度因不同的严重急性呼吸综合征冠状病毒 2 变异株是否不同，目前证据有限。我们比较了在挪威，未接种疫苗的<18 岁人群中，与 COVID-19（病例）相关的 Alpha、Delta 和奥密克戎（BA.1 亚系）变异株波之间，因急性 COVID-19 或儿童多系统炎症综合征（MIS-C）住院的风险。
我们使用国家登记处的个体水平数据，使用多变量对数二项式回归计算调整后的风险比（aRR）及其 95%置信区间（CI）。我们调整了变异株波、人口统计学特征和潜在合并症。
我们纳入了 10538 例 Alpha（21 例急性 COVID-19，7 例 MIS-C）、42362 例 Delta（28 例急性 COVID-19，14 例 MIS-C）和 82907 例奥密克戎波病例（48 例急性 COVID-19，7 例 MIS-C）。与 Alpha 波相比，Delta（aRR：0.53，95%CI：0.30-0.93）和奥密克戎波（aRR：0.40，95%CI：0.24-0.68）的急性 COVID-19 住院风险较低。与 Delta 相比，我们发现奥密克戎的这种风险没有差异。与 Alpha（aRR：0.09，95%CI：0.03-0.27）和 Delta（aRR：0.26，95%CI：0.10-0.63）相比，奥密克戎的 MIS-C 风险较低。
我们没有明确的证据表明，不同的变异株会影响挪威未接种疫苗的儿童和青少年因急性 COVID-19 住院的风险。奥密克戎和 Delta 的这种结果风险较低可能反映了随着时间的推移其他因素的变化，如检测策略、母体疫苗接种和/或住院标准。奥密克戎的出现降低了 MIS-C 的风险。
