目的 探讨新型冠状病毒（SARS-CoV-2）感染无症状患儿的临床及流行病学特征。方法 收集2020年1月20日至3月4日确诊为SARS-CoV-2感染无症状患儿20例的临床资料并进行分析。结果 20例患儿中，男7例（35%），女13例（65%）；年龄8个月至14岁，平均年龄8±5岁；均无临床表现但因具有流行病学史就诊。20例患儿中，19例为家庭聚集性发病；鼻咽拭子SARS-CoV-2核酸检测均阳性，其中轻型4例（20%），普通型16例（80%），无重型和危重型；外周血白细胞计数（6.8±3.5）×10⁹/L，其中7例结果异常，5例升高，2例降低；1例患儿淋巴细胞绝对值降低（0.87×10⁹/L）；3例患儿红细胞沉降率升高（20~42 mm/h）；7例患儿乳酸脱氢酶水平升高（> 400 U/L）；4例患儿血乳酸水平升高（> 1.6 mmol/L）。胸部CT显示13例患儿肺部影像学以单发或多发的肺叶中外带或胸膜下小结节影、斑片状影和磨玻璃样影为主要特征。结论 无症状SARS-CoV-2感染儿童病例以家庭聚集性发病为主。大部分无症状感染患儿的血常规及其他实验室检查指标无明显异常；胸部CT改变可作为无症状感染患儿早期诊断的辅助手段。

Objective To study the clinical and epidemiological features of children with asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Methods The clinical data of 20 children who were diagnosed with asymptomatic SARS-CoV-2 infection from January 20 to March 4, 2020 were analyzed. Results Among the 20 children, there were 7 boys (35%) and 13 girls (65%), aged 8 months to 14 years (mean 8±5 years). All these children had no clinical manifestations and attended the hospital for an epidemiological history of SARS-CoV-2. Nineteen children were shown with family aggregation of SARS-CoV-2 infection. Nasopharyngeal swabs were PCR-positive for SARS-CoV-2 in all 20 children. There were 4 children (20%) of mild type, 16 children (80%) of common type, and no children of severe type or critical type. The mean peripheral blood leukocyte count was (6.8±3.5)×10⁹/L, and 7 children had an abnormal peripheral blood leukocyte count, with an increase in 5 children and a reduction in 2 children. One child had a decreased absolute value of lymphocytes (0.87×10⁹/L), 3 children had an increased erythrocyte sedimentation rate (20-42 mm/h), 7 children had an increased lactate dehydrogenase level (> 400 U/L), and 4 children had an increased blood lactate level (> 1.6 mmol/L). Chest CT showed single or multiple small nodule shadows, patchy shadows, and ground-glass shadows in the middle or lateral lobe of lungs or under the pleura in 13 children. Conclusions Pediatric cases of asymptomatic SARS-CoV-2 infection mostly occur with family aggregation. Most of the children with asymptomatic infection have no obvious abnormalities in blood routine and other laboratory tests. Changes in chest CT scan can be used as an aid for early diagnosis of asymptomatic infection in children.