While children get much milder COVID-19 than adults, risk factors for severe illness remain unclear. US researchers used a dedicated COVID-19 database with data from 43 465 children ≤18 years to examine risk factors for both hospital admission and severe illness.¹ All had an emergency department or inpatient encounter from March 2020 to January 2021 (pre-delta) and all had proven SARS-CoV-2 infection. Severe illness was defined as requiring intensive care, invasive mechanical ventilation or death. Multivariate analysis was used to control for patient and hospital characteristics in calculating risk factors for admission and severe disease. The main medical conditions associated with increased risk of hospital admission were type 1 diabetes (adjusted risk ratio (aRR) = 4.60, 95% confidence interval (CI) 3.91–5.42), obesity (aRR 3.07, 95% CI 2.66–3.54) and children defined as having ‘complex chronic disease’ (aRR 7.86, 95% CI 6.91–8.95). The main medical conditions associated with severe illness were type 1 diabetes (aRR = 2.38, 95% CI 2.06–2.76), cardiac and circulatory congenital heart anomalies, that is congenital heart disease (aRR 1.72, 95% CI 1.48–1.99), epilepsy (aRR 1.71, 95% CI 1.41–2.08), see Figure 1, and chronic and complex chronic disease (aRR 2.86, 95% CI 2.47–3.32). While considerably larger than other studies, there are limitations. In particular, the retrospective design precludes assigning causation. For example, children with type 1 diabetes or convulsions might be admitted to hospital or intensive care because of their underlying condition, and SARS-CoV-2 infection was almost incidental. Despite the limitations of this observational data, the results provide useful information on which to base targeted COVID-19 immunisation of children at greater risk of a bad outcome.

虽然儿童感染 COVID-19 的症状比成人轻得多，但严重疾病的风险因素仍不清楚。美国研究人员使用了一个专门的 COVID-19 数据库，其中包含来自 43465 名 18 岁以下儿童的数据，以检查入院和重病的危险因素。¹从 2020 年 3 月到 2021 年 1 月（三角洲前），所有人都曾在急诊室或住院部就诊，并且都被证明感染了 SARS-CoV-2。严重疾病被定义为需要重症监护、有创机械通气或死亡。在计算入院和重症危险因素时，采用多变量分析控制患者和医院特征。与住院风险增加相关的主要疾病是 1 型糖尿病（调整后风险比 (aRR) = 4.60，95% 置信区间 (CI) 3.91–5.42）、肥胖（aRR 3.07，95% CI 2.66–3.54）和定义为“复杂慢性病”的儿童（aRR 7.86，95% CI 6.91–8.95）。与严重疾病相关的主要疾病是 1 型糖尿病 (aRR = 2.38, 95% CI 2.06–2.76)、心脏和循环先天性心脏异常、即先天性心脏病 (aRR 1.72, 95% CI 1.48–1.99)、癫痫 (aRR 1.71, 95% CI 1.41–2.08)，见图 1，以及慢性和复杂慢性疾病 (aRR 2.86, 95% CI 2.47–33)。 ）。虽然比其他研究大得多，但也有局限性。特别是，追溯设计排除了因果关系。例如，患有 1 型糖尿病或抽搐的儿童可能会因为其潜在疾病而被送入医院或重症监护室，而 SARS-CoV-2 感染几乎是偶然的。尽管这些观察性数据存在局限性，但结果提供了有用的信息，可以据此对有更大风险的不良结果的儿童进行针对性的 COVID-19 免疫。95% 置信区间 2.47–3.32）。虽然比其他研究大得多，但也有局限性。特别是，追溯设计排除了因果关系。例如，患有 1 型糖尿病或抽搐的儿童可能会因为其潜在疾病而被送入医院或重症监护室，而 SARS-CoV-2 感染几乎是偶然的。尽管这些观察性数据存在局限性，但结果提供了有用的信息，可以据此对有更大风险的不良结果的儿童进行针对性的 COVID-19 免疫。95% 置信区间 2.47–3.32）。虽然比其他研究大得多，但也有局限性。特别是，追溯设计排除了因果关系。例如，患有 1 型糖尿病或抽搐的儿童可能会因为其潜在疾病而被送入医院或重症监护室，而 SARS-CoV-2 感染几乎是偶然的。尽管这些观察性数据存在局限性，但结果提供了有用的信息，可以据此对有更大风险的不良结果的儿童进行针对性的 COVID-19 免疫。SARS-CoV-2 感染几乎是偶然的。尽管这些观察性数据存在局限性，但结果提供了有用的信息，可以据此对有更大风险的不良结果的儿童进行针对性的 COVID-19 免疫。SARS-CoV-2 感染几乎是偶然的。尽管这些观察性数据存在局限性，但结果提供了有用的信息，以此为基础对具有更大不良结果风险的儿童进行针对性的 COVID-19 免疫。