Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
Department of Paediatrics, Orebro University Hospital, Orebro, Sweden.
Acta Paediatr. 2020 Aug;109(8):1525-1530. doi: 10.1111/apa.15371. Epub 2020 Jun 17.
Many countries have closed schools and kindergartens to minimise COVID-19, but the role that children play in disease transmission is unclear.
A systematic literature review of the MEDLINE and EMBASE databases and medRxiv/bioRxiv preprint servers to 11 May 2020 identified published and unpublished papers on COVID-19 transmission by children.
We identified 700 scientific papers and letters and 47 full texts were studied in detail. Children accounted for a small fraction of COVID-19 cases and mostly had social contacts with peers or parents, rather than older people at risk of severe disease. Data on viral loads were scarce, but indicated that children may have lower levels than adults, partly because they often have fewer symptoms, and this should decrease the transmission risk. Household transmission studies showed that children were rarely the index case and case studies suggested that children with COVID-19 seldom caused outbreaks. However, it is highly likely that children can transmit the SARS-COV-2 virus, which causes COVID-19, and even asymptomatic children can have viral loads.
Children are unlikely to be the main drivers of the pandemic. Opening up schools and kindergartens is unlikely to impact COVID-19 mortality rates in older people.
许多国家已经关闭学校和幼儿园以最大程度减少 COVID-19 的传播，但儿童在疾病传播中的作用尚不清楚。
对截至 2020 年 5 月 11 日的 MEDLINE 和 EMBASE 数据库以及 medRxiv/bioRxiv 预印本服务器进行了系统的文献回顾，以确定有关儿童传播 COVID-19 的已发表和未发表的论文。
我们共检索到 700 篇科学论文和信件，其中 47 篇全文进行了详细研究。儿童在 COVID-19 病例中占很小的比例，且主要与同龄人或父母有社交接触，而不是与高危重病的老年人接触。关于病毒载量的数据很少，但表明儿童的病毒载量可能低于成人，部分原因是他们通常症状较少，这应降低传播风险。家庭传播研究表明，儿童很少是首发病例，病例研究表明，患有 COVID-19 的儿童很少引起暴发。但是，儿童极有可能传播导致 COVID-19 的 SARS-COV-2 病毒，甚至无症状的儿童也可能具有病毒载量。
儿童不太可能是大流行的主要驱动因素。开放学校和幼儿园不太可能对老年人的 COVID-19 死亡率产生影响。
