Feasibility and efficacy of mass testing for SARS-CoV-2 in a UK university using swab pooling and PCR

Abstract

Transmission of SARS-CoV-2 without symptoms is well described, and may be mitigated by mass testing. Nonetheless, the optimal implementation and quantitative real-world impact of this approach remain unclear. During a period of rising SARS-CoV-2 prevalence, students at the University of Cambridge were enrolled in a voluntary programme of weekly PCR-based asymptomatic screening. Swab pooling by household reduced the total testing capacity required by five-fold, without affecting laboratory workflows or compromising test sensitivity. Participation remained >75% throughout the study period. 299/671 (45%) of students diagnosed with SARS-CoV-2 were either identified or pre-emptively quarantined because of the screening programme. After a negative screening test, the risk of developing COVID-19 over the following 7 days was decreased by 51%. Modelling transmission using parameters from our study suggests a reduction in R0 of up to 31% attributable to weekly screening. We therefore demonstrate the feasibility and efficacy of regular, voluntary mass testing for COVID-19.

Heat Inactivation of Clinical COVID-19 Samples on an Industrial Scale for Low Risk and Efficient High-throughput qRT-PCR Diagnostic Testing

“…S3). Additionally, as the CCTC also analysed pooled OP/NP tests supplied by the University of Cambridge containing up to 10 swabs in a single tube [21], we also con rmed that vials containing multiple OP/NP swabs performed similarly to vials containing single swabs. We observed a 4 minute time difference before reaching the required 65°C, but no additional over-heating (Supplementary Fig.…”

An iteratively optimised process for improving the efficiency and effectiveness of an industrial SARS-CoV-2 diagnostic facility

“…The CCTC is unique in many ways to other local and national COVID-19 diagnostic laboratories, as in addition to processing the normal single swab samples, the centre also evolved a process for pooled patient swab samples from the University of Cambridge Asymptomatic Testing Programme for its students 12,13 and testing of staff samples from the local NHS Trust hospital (Addenbrooke's Hospitalthe largest in the East of England). The centre also employed a dedicated technology development team involved in research activities leading to pioneering innovations for improving the safety, e ciency, robustness, and portability of the COVID-19 screening process.…”

Mass testing of university students for covid-19

“…The data also show that mass testing can markedly increase case ascertainment, including a substantial proportion of people who have yet to develop symptoms (pre-symptomatic infection) 9131415. During certain stages of the pandemic, some universities detected more students with SARS-CoV-2 infection through asymptomatic screening than through symptomatic testing 141516.…”

“…The evidence suggests it is possible to sustain high levels of adherence to regular, voluntary, asymptomatic screening using nose and throat swabs 89. University led testing programmes have been strongly supported by students,81011 providing reassurance at a time when student mental health and wellbeing have been severely affected by the pandemic 812…”

“…PCR testing seems ideally suited to regular screening of defined populations, since high test sensitivity minimises the risk of false negative results and samples are available for genomic sequencing 17. In a university context, laboratory and logistical infrastructure can be planned in advance, turnaround time minimised, and swab or sample pooling used to reduce costs and demands on testing capacity, particularly when incidence is low 91518. False positive results can often be reduced by a two-step testing strategy, whereby a positive screening test result is followed routinely by a confirmatory PCR test 9.…”