Young 2021.

Study characteristics
Methods	Cluster‐randomised, controlled trial of daily contact testing in students and staff at secondary schools and colleges in England to show whether daily contact testing increases school attendance and to assess the impact of daily contact testing on SARS‐CoV‐2 transmission within schools.
Participants	201 schools, of which 99 were randomly assigned to self‐isolation of school‐based COVID‐19 contacts for 10 days (control) and 102 to voluntary daily lateral flow device (LFD) testing for 7 days with LFD‐negative contacts remaining at school (intervention)
Interventions	All schools in the intervention and control groups followed the national policy of offering twice weekly asymptomatic testing with LFDs. Individuals with positive LFD results were required to self‐isolate immediately and requested to obtain a confirmatory PCR test within 2 days. Those with indicator symptoms of possible COVID‐19 (new cough, fever, loss or change in taste or smell) were required to self‐isolate along with their household and obtain an urgent PCR test. If a student or staff member tested positive by LFD or PCR, close contacts (hereafter referred to as contacts) were identified by schools using national guidelines. Those in close contact with a case less than 48 hours before symptom onset (or a positive test if asymptomatic) were required to self‐isolate for 10 days. At schools in the intervention group, contacts were offered daily contact testing as an alternative to self‐isolation, provided the contact was school‐based (i.e. with a staff member or student), the contact did not have indicator symptoms of COVID‐19, and contacts were able to attend for on‐site testing at school. See Table 4 for details.
Outcomes	Laboratory PCR confirmed infections Effectiveness COVID‐19‐related school absence and symptomatic PCR‐confirmed COVID‐19. Safety NR
Notes	The authors conclude that quote: “Daily contact testing of school‐based contacts was non‐inferior to self‐isolation for control of COVID‐19 transmission, with similar rates of symptomatic infections among students and staff with both approaches." Funding: UK Government Department of Health and Social Care. Declaration of interests: DWE reports lecture fees from Gilead outside the submitted work. VB, RO, and DC are consultants employed by Department of Health and Social Care as part of Deloitte’s broader project work supporting the delivery of NHS Test and Trace. TF reports honoraria from Qatar National Research Fund outside the submitted work. All other authors declare no competing interests. Potential conflicts of interest: all authors report no conflicts of interest relevant to this article.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer random‐number generator
Allocation concealment (selection bias)	Unclear risk	Insufficient information reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded.
Incomplete outcome data (attrition bias) All outcomes	High risk	Participant flow diagram reported showing high attrition at different rates in the 2 groups
Selective reporting (reporting bias)	Low risk	Prespecified outcomes reported