Public Health Sciences, Clemson University, Clemson, South Carolina, USA
Public Health Sciences, Clemson University, Clemson, South Carolina, USA.
BMJ Open. 2020 Dec 15;10(12):e042578. doi: 10.1136/bmjopen-2020-042578.
Universities are exploring strategies to mitigate the spread of COVID-19 prior to reopening their campuses. National guidelines do not currently recommend testing students prior to campus arrival. However, the impact of presemester testing has not been studied.
Dynamic SARS-CoV-2 transmission models are used to explore the effects of three presemester testing interventions.
Testing of students 0, 1 and 2 times prior to campus arrival.
Number of active infections and time until isolation bed capacity is reached.
We set on-campus and off-campus populations to 7500 and 17 500 students, respectively. We assumed 2% prevalence of active cases at the semester start, and that one-third of infected students will be detected and isolated throughout the semester. Isolation bed capacity was set at 500. We varied disease transmission rates (R=1.5, 2, 3, 4) to represent the effectiveness of mitigation strategies throughout the semester.
Without presemester screening, peak number of active infections ranged from 4114 under effective mitigation strategies (R=1.5) to 10 481 under ineffective mitigation strategies (R=4), and exhausted isolation bed capacity within 10 (R =4) to 25 days (R=1.5). Mandating at least one test prior to campus arrival delayed the timing and reduced the size of the peak, while delaying the time until isolation bed capacity was reached. Testing twice in conjunction with effective mitigation strategies (R=1.5) was the only scenario that did not exhaust isolation bed capacity during the semester.
Presemester screening is necessary to avert early and large surges of active COVID-19 infections. Therefore, we recommend testing within 1 week prior to and on campus return. While this strategy is sufficient for delaying the timing of the peak outbreak, presemester testing would need to be implemented in conjunction with effective mitigation strategies to significantly reduce outbreak size and preserve isolation bed capacity.
在重新开放校园之前，大学正在探索减轻 COVID-19 传播的策略。国家指南目前不建议在到校前对学生进行检测。然而，课前检测的影响尚未得到研究。
使用动态 SARS-CoV-2 传播模型来探索三种课前检测干预措施的效果。
在到校前检测学生 0、1 和 2 次。
活跃感染的数量和达到隔离床位容量的时间。
我们将校内和校外人群分别设置为 7500 人和 17500 人。我们假设在学期开始时活跃病例的患病率为 2%，并且三分之一的感染学生将在整个学期内被发现和隔离。隔离床位容量设定为 500。我们改变了疾病传播率（R=1.5、2、3、4），以代表整个学期缓解策略的有效性。
在没有课前筛查的情况下，活跃感染的峰值数量从有效缓解策略（R=1.5）下的 4114 例到无效缓解策略（R=4）下的 10481 例不等，并且在 10 天（R=4）内隔离床位容量耗尽到 25 天（R=1.5）。在到校前至少进行一次检测会延迟时间并减少峰值的大小，同时延迟达到隔离床位容量的时间。与有效缓解策略（R=1.5）一起进行两次检测是唯一一种在整个学期内不会耗尽隔离床位容量的方案。
课前筛查对于避免 COVID-19 活跃感染的早期和大规模激增是必要的。因此，我们建议在返校前 1 周内进行检测。虽然这种策略足以延迟高峰爆发的时间，但课前检测需要与有效的缓解策略相结合，以显著减少爆发规模并保留隔离床位容量。
