Transmission of SARS-CoV-2 by children to contacts in schools and households: a prospective cohort and environmental sampling study in London.
Transmission of SARS-CoV-2 by children to contacts in schools and households: a prospective cohort and environmental sampling study in London.
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DOI：
10.1016/s2666-5247(22)00124-0
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发表时间：
2022-11
期刊：
影响因子：
38.2
通讯作者：
Sriskandan, Shiranee
中科院分区：
文献类型：
--
作者：
Cordery, Rebecca;Reeves, Lucy;Zhou, Jie;Rowan, Aileen;Watber, Patricia;Rosadas, Carolina;Crone, Michael;Starch, Marko;Freemont, Paul;Mosscrop, Lucy;Cowley, Alice;Zefent, Gina;Bisset, Kate;Le Blond, Holly;Regmi, Sadie;Buckingham, Christian;Junaideen, Ramlah;Abdulla, Nadia;Eliahoo, Joseph;Mindlin, Miranda;Lamagni, Theresa;Barclay, Wendy;Taylor, Graham P.;Sriskandan, Shiranee
评估SARS-CoV-2在学校的传播情况对于为公共卫生行动提供信息至关重要。我们评估了学校和家庭中接触COVID-19的学生获得SARS-CoV-2的频率，并量化了SARS-CoV-2在两种环境中进入空气和污染物的情况。我们在英国伦敦的八所学校进行了前瞻性队列和环境抽样研究。向当地卫生保护小组报告新的SARS-CoV-2感染病例的学校，如果在SARS-CoV-2 PCR检测呈阳性前48小时内有儿童索引病例上学，则被邀请参加。在研究时，PCR检测仅适用于有症状的个体。纳入了2-14岁（2020年11月延长至<18岁）的儿童，这些儿童从认可的实验室获得了新的鼻或咽拭子SARS-CoV-2阳性PCR。确定了涉及暴露于至少一名患有COVID-19的指数瞳孔的事件（主要变体为原始、α和δ）。每周对直接课堂接触者（所谓的气泡）、非气泡学校接触者和索引学生的家庭接触者进行SARS-CoV-2 PCR检测。测试得到了基因组测序以及来自学校和家庭环境的表面和空气样本的支持。在2020年10月至2021年7月期间，从所包括的8所学校中，在28名泡沫接触者中未检测到SARS-CoV-2的继发性传播，代表10个泡沫班（参与率为8.8%[IQR 4.6 - 15.3]）。在8个非气泡班中，62名学生中有3名（2%）检测呈阳性，但这些与原始指示病例无关（参与率22.5%[9.7 - 32.3]）。这三人都没有症状，并在同一天的一次测试中呈阳性。相比之下，在35个家庭接触者中有6个（17%）被发现从受感染的指标学生向先前阴性家庭接触者的二次传播，在考虑家庭接触者中的所有潜在感染时，这一比例上升到47个家庭接触者中的13个（28%）。SARS-CoV-2的环境污染在学校中很少见：泡沫教室的189个样本中有4个（2%）被确定为污染物SARS-CoV-2，非泡沫教室的127个样本中有2个（2%），洗手间的130个样本中有5个（4%）。这与家庭中的污染物形成鲜明对比，其中SARS-CoV-2在248个卧室样本中的60个（24%），241个公共房间样本中的66个（27%）和188个浴室样本中的21个（11%）中被确定。在68份学校空气样本中，只有1份（2%）发现了SARS-CoV-2 RNA，而在85份家庭空气样本中，有21份（25%）发现了SARS-CoV-2 RNA。没有证据表明在采取预防措施的学校中发生大规模SARS-CoV-2传播。学校环境污染程度低与传播频率低是一致的，这表明在研究期间学校有足够的清洁和通风。家庭中二次传播的频率很高，与整个家庭中明显的病毒散发有关，这表明有必要改善对儿童感染家庭的建议，以防止进一步的社区传播。这些数据表明，当预防措施减少时，任何环境中的儿童都很可能发生SARS-CoV-2传播。英国研究与创新部、英国卫生与社会保障部、英国国家卫生与保健研究所
Assessing transmission of SARS-CoV-2 by children in schools is of crucial importance to inform public health action. We assessed frequency of acquisition of SARS-CoV-2 by contacts of pupils with COVID-19 in schools and households, and quantified SARS-CoV-2 shedding into air and onto fomites in both settings. We did a prospective cohort and environmental sampling study in London, UK in eight schools. Schools reporting new cases of SARS-CoV-2 infection to local health protection teams were invited to take part if a child index case had been attending school in the 48 h before a positive SARS-CoV-2 PCR test. At the time of the study, PCR testing was available to symptomatic individuals only. Children aged 2–14 years (extended to <18 years in November, 2020) with a new nose or throat swab SARS-CoV-2 positive PCR from an accredited laboratory were included. Incidents involving exposure to at least one index pupil with COVID-19 were identified (the prevailing variants were original, α, and δ). Weekly PCR testing for SARS-CoV-2 was done on immediate classroom contacts (the so-called bubble), non-bubble school contacts, and household contacts of index pupils. Testing was supported by genome sequencing and on-surface and air samples from school and home environments. Between October, 2020, and July, 2021 from the eight schools included, secondary transmission of SARS-CoV-2 was not detected in 28 bubble contacts, representing ten bubble classes (participation rate 8·8% [IQR 4·6–15·3]). Across eight non-bubble classes, 3 (2%) of 62 pupils tested positive, but these were unrelated to the original index case (participation rate 22·5% [9·7–32·3]). All three were asymptomatic and tested positive in one setting on the same day. In contrast, secondary transmission to previously negative household contacts from infected index pupils was found in six (17%) of 35 household contacts rising to 13 (28%) of 47 household contacts when considering all potential infections in household contacts. Environmental contamination with SARS-CoV-2 was rare in schools: fomite SARS-CoV-2 was identified in four (2%) of 189 samples in bubble classrooms, two (2%) of 127 samples in non-bubble classrooms, and five (4%) of 130 samples in washrooms. This contrasted with fomites in households, where SARS-CoV-2 was identified in 60 (24%) of 248 bedroom samples, 66 (27%) of 241 communal room samples, and 21 (11%) 188 bathroom samples. Air sampling identified SARS-CoV-2 RNA in just one (2%) of 68 of school air samples, compared with 21 (25%) of 85 air samples taken in homes. There was no evidence of large-scale SARS-CoV-2 transmission in schools with precautions in place. Low levels of environmental contamination in schools are consistent with low transmission frequency and suggest adequate cleaning and ventilation in schools during the period of study. The high frequency of secondary transmission in households associated with evident viral shedding throughout the home suggests a need to improve advice to households with infection in children to prevent onward community spread. The data suggest that SARS-CoV-2 transmission from children in any setting is very likely to occur when precautions are reduced. UK Research and Innovation and UK Department of Health and Social Care, National Institute for Health and Care Research