研究人员发现，与年龄较大的儿童和成人相比，患有轻度或中度COVID-19的5岁以下儿童的鼻内病毒遗传物质水平要高得多。研究结果指出，幼儿可能与其他年龄组人群一样传播病毒。

Young kids could spread COVID-19 as much as older children and adults, study suggests

https://www.sciencedaily.com/releases/2020/07/200730141324.htm

Taylor Heald-Sargent, William J. Muller, Xiaotian Zheng, Jason Rippe, Ami B. Patel, Larry K. Kociolek. Age-Related Differences in Nasopharyngeal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Levels in Patients With Mild to Moderate Coronavirus Disease 2019 (COVID-19). JAMA Pediatrics, July 30, 2020; DOI: 10.1001/jamapediatrics.2020.3651