Background

Little is known about the risk of SARS-CoV-2 infection and transmission in educational settings. Public Health England initiated a study, COVID-19 Surveillance in School KIDs (sKIDs), in primary schools when they partially reopened from June 1, 2020, after the first national lockdown in England to estimate the incidence of symptomatic and asymptomatic SARS-CoV-2 infection, seroprevalence, and seroconversion in staff and students.

Methods

sKIDs, an active, prospective, surveillance study, included two groups: the weekly swabbing group and the blood sampling group. The swabbing group underwent weekly nasal swabs for at least 4 weeks after partial school reopening during the summer half-term (June to mid-July, 2020). The blood sampling group additionally underwent blood sampling for serum SARS-CoV-2 antibodies to measure previous infection at the beginning (June 1–19, 2020) and end (July 3–23, 2020) of the summer half-term, and, after full reopening in September, 2020, and at the end of the autumn term (Nov 23–Dec 18, 2020). We tested for predictors of SARS-CoV-2 antibody positivity using logistic regression. We calculated antibody seroconversion rates for participants who were seronegative in the first round and were tested in at least two rounds.

Findings

During the summer half-term, 11 966 participants (6727 students, 4628 staff, and 611 with unknown staff or student status) in 131 schools had 40 501 swabs taken. Weekly SARS-CoV-2 infection rates were 4·1 (one of 24 463; 95% CI 0·1–21·8) per 100 000 students and 12·5 (two of 16 038; 1·5–45·0) per 100 000 staff. At recruitment, in 45 schools, 91 (11·2%; 95% CI 7·9–15·1) of 816 students and 209 (15·1%; 11·9–18·9) of 1381 staff members were positive for SARS-CoV-2 antibodies, similar to local community seroprevalence. Seropositivity was not associated with school attendance during lockdown (p=0·13 for students and p=0·20 for staff) or staff contact with students (p=0·37). At the end of the summer half-term, 603 (73·9%) of 816 students and 1015 (73·5%) of 1381 staff members were still participating in the surveillance, and five (four students, one staff member) seroconverted. By December, 2020, 55 (5·1%; 95% CI 3·8–6·5) of 1085 participants who were seronegative at recruitment (in June, 2020) had seroconverted, including 19 (5·6%; 3·4–8·6) of 340 students and 36 (4·8%; 3·4–6·6) of 745 staff members (p=0·60).

Interpretation

In England, SARS-CoV-2 infection rates were low in primary schools following their partial and full reopening in June and September, 2020.

Funding

UK Department of Health and Social Care.

中文翻译：

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2020 年 6 月至 12 月英格兰小学的 SARS-CoV-2 感染和传播（sKIDs）：一项积极的前瞻性监测研究

背景

人们对教育环境中 SARS-CoV-2 感染和传播的风险知之甚少。英格兰公共卫生部在英格兰首次全国封锁后于 2020 年 6 月 1 日部分重新开放的小学开始了一项名为“学校儿童 COVID-19 监测”(sKIDs) 的研究，以估计有症状和无症状 SARS-CoV 的发生率。 2 教职员工和学生的感染、血清阳性率和血清转化。

方法

sKIDs 是一项积极的前瞻性监测研究，包括两组：每周擦拭组和采血组。在夏季半学期（2020 年 6 月至 7 月中旬）部分学校重新开学后，拭子组每周接受鼻拭子检查至少 4 周。采血组在夏季学期开始（2020 年 6 月 1 日至 19 日）和结束（2020 年 7 月 3 日至 23 日）时还进行了血清 SARS-CoV-2 抗体采血，以测量先前的感染情况，并且，在 2020 年 9 月全面重新开放后和秋季学期结束时（2020 年 11 月 23 日至 12 月 18 日）。我们使用逻辑回归测试了 SARS-CoV-2 抗体阳性的预测因子。我们计算了第一轮血清反应阴性并至少接受两轮测试的参与者的抗体血清转化率。

发现

在夏季期中，131 所学校的 11 966 名参与者（6 727 名学生、4 628 名教职员工和 611 名教职员工或学生身份不详的人）采集了 40 501 支拭子。每周 SARS-CoV-2 感染率为每 100 000 名学生 4·1（24463 人中的一人；95% CI 0·1–21·8）和 12·5（16038 人中的两人；1·5–45·0 ) 每 100 000 名员工。在招聘时，在 45 所学校中，816 名学生中有 91 名（11·2%；95% CI 7·9–15·1）和 1381 名教职员工中有 209 名（15·1%；11·9–18·9）是积极的对于 SARS-CoV-2 抗体，类似于当地社区的血清阳性率。血清阳性与锁定期间的学校出勤率（学生 p=0·13 和工作人员 p=0·20）或工作人员与学生接触（p=0·37）无关。暑假期末，816 名学生中的 603 人（73·9%）和 1381 名工作人员中的 1015 人（73·5%）仍在参与监测，5 名（4 名学生，一名工作人员）血清转化。到 2020 年 12 月，招募时（2020 年 6 月）血清反应呈阴性的 1085 名参与者中有 55 人（5·1%；95% CI 3·8–6·5）发生了血清转化，其中 19 人（5·6%；3· 4–8·6) 的 340 名学生和 36 (4·8%; 3·4–6·6) 的 745 名员工 (p=0·60)。

解释

在英格兰，在 2020 年 6 月和 2020 年 9 月部分和全部重新开放后，小学的 SARS-CoV-2 感染率很低。

资金

英国卫生和社会保健部。