BACKGROUND Pediatric patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) displayed milder symptoms than adults. However, they play an important role in case numbers and virus transmission. Therefore, we aimed to determine the epidemiological features of all pediatric patients infected with SARS-CoV-2 and put forth case numbers longitudinally throughout the delta variant dominant period. METHODS A retrospective study was conducted at a university hospital and included patients between 0 and18 years old with a SARS-CoV-2 polymerase chain reaction (PCR) positive result, including inpatients and outpatients. Epidemiological and clinical features were recorded from electronic files, and telephone visits were performed between March 2020 and December 2021. RESULTS During the study period, 3175 coronavirus disease 2019 (COVID-19) pediatric patients were admitted to our hospital with a mean age of 10.61 ± 4.6 years. Of the 1815 patients who could be interviewed, 85.7% reported at least one symptom. Before the delta variant period, 0-4 years aged children were more commonly infected, while school-aged children and adolescents were more common, and the rate of pediatric cases to all COVID-19 cases increased to 35.8% after the delta variant became dominant. Symptomatic cases were significantly higher before the delta variant (87.8% vs. 84.06%, p = 0.016). The hospitalization rate was higher before the delta variant (p < 0.001), whereas PICU admission showed no statistical difference. CONCLUSIONS The frequency of school-aged children and adolescents raised with the impact of both school openings and the delta variant, and the rate of pediatric cases increased in total COVID-19 patient numbers.

中文翻译：

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儿科患者 COVID-19 的纵向评估和 delta 变异的影响。

背景 感染严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 的儿科患者表现出比成人更轻的症状。但是，它们在病例数和病毒传播方面发挥着重要作用。因此，我们旨在确定所有感染 SARS-CoV-2 的儿科患者的流行病学特征，并纵向列出整个 delta 变异显性期的病例数。方法 在一所大学医院进行了一项回顾性研究，纳入了 0 至 18 岁且 SARS-CoV-2 聚合酶链反应 (PCR) 阳性结果的患者，包括住院患者和门诊患者。从电子文件中记录流行病学和临床特征，并在 2020 年 3 月至 2021 年 12 月期间进行电话访问。结果在研究期间，我们医院收治了 3175 名 2019 冠状病毒病 (COVID-19) 儿科患者，平均年龄为 10.61 ± 4.6 岁。在接受采访的 1815 名患者中，85.7% 报告了至少一种症状。在delta变异期之前，0-4岁儿童更易感染，而学龄儿童和青少年更常见，delta变异占主导地位后，儿科病例占所有COVID-19病例的比例增加到35.8% . 在 delta 变异之前有症状的病例明显更高（87.8% 对 84.06%，p = 0.016）。住院率在 delta 变体之前更高 (p < 0.001)，而 PICU 入院率没有统计学差异。结论 学龄儿童和青少年的出现频率随着学校开学和三角洲变体的影响而提高，