Daily contact testing schools and colleges trial

Co-Primary End-Points:
1. Number of school days missed among those eligible to be in school during the 9-week period of the study. Daily school attendances will be obtained from the school register and absences recorded with reconciliation with COVID-19 associated absences. This will be compared between study arms, to historic schools’ data, and to national schools’ benchmark data collected via a survey of non-participating schools.
2. Estimated number of in-school COVID-19 transmission events during the 9-week period of the study: the number of positive cases will be obtained from the following sources:
2.1. Weekly LFD active case finding (control and intervention arms) during the 9-week period of the study
2.2. Symptomatic individuals’ NHS Test and Trace results obtained from Community Testing routine data (control and intervention arms) during the 9-week period of the study
2.3. In-school LFD DCT testing (intervention arm) during the 9-week period of the study
Positivity rates will be reported for each source separately to facilitate like-for-like comparison between arms

Epidemiological links between cases will be obtained from the NHS Test & Trace Contact Tracing and Advice Service database. Additional links will be obtained by membership of school-reported contact groups. Onward transmission from the index case will be determined by the following:
1. Genomic sequence of virus: the additional PCR swab collected from positive individuals will be used to determine the whole genomic sequence of isolates. A sample of apparent links will be assessed with comparisons of whole-genome sequencing. The diversity of genetic sequences both in the schools and the community (routinely determined by COG) will be used to help interpret the results. Preliminary work currently undertaken will determine the appropriate genetic distance to be used to exclude a direct transmission event between individuals. This is likely to be two SNPs.
2. Plausible epidemiological link (e.g. membership of same close contact group)
3. For positive individuals identified in DCT the DMIC will review all available data to determine if the individual’s infection was likely to have resulted from onward transmission from the index case, or via co-infection from an unknown ‘upstream’ positive or out-of-school positive case.

1. Number of positive first-order contacts missed by daily LFD testing during the 9-week period of the study (intervention arm only). Routine qPCR of first-order contacts will be used to determine the performance of DCT testing with LFDs. Comparisons of PCR with the same day LFD will allow comparison between CT values and LFD results in a ‘real world setting’ These comparisons can also be used to compare the relative performance between assisted school-based testing and home/self-testing.
2. Number of COVID-19 cases transmitted to the first-order contacts of index cases during the 9-week period of the study (“primary attack rate”). The first-order close contacts of all index cases will be identified by the school based on their existing close contact management policy. LFD DCT testing and (for symptomatic individuals) routine NHS Test and Trace PCR testing will be used to calculate the primary attack rate. As above, genomic sequencing will be used, wherever possible, to exclude non-direct transmission events.
3. Number of COVID-19 cases transmitted to the second-order contacts of index cases during the 9-week period of the study (“secondary attack rate”). The second-order contacts of all index cases will be identified (regardless of the COVID-19 status of the DCT-contacts) as described in Section 3.7. The COVID-19 status of these second-order contacts will be measured in two ways:
3.1. Where the second-order contact is a consented participant in this study their COVID-19 status will be assessed by weekly LFD active case finding during the 9-week period of the study, and records kept by the school of any participants who become symptomatic and test positive via standard NHS Test and Trace community testing.
3.2. Where the second-order contact is not a consented participant in this study (e.g., household contact of the first-order contact), analysis of routine NHS Test and Trace data recorded during the 9-week period of the study will be used to determine if they subsequently become symptomatic and test positive in the community setting. As above, genomic sequencing will be used, wherever possible, to exclude non-direct transmission events.
4. Number and proportion of school attendees testing COVID-19 positive in weekly active case finding during the 9-week period of the study. LFD results and school attendance registers will be used to calculate the active case finding rate. This will be compared between study arms, and to national schools’ benchmark data collected via a survey of non-participating schools.
5. Proportion of student and staff who accept an offer of weekly active case finding testing with LFD devices during the 9-week period of the study. Schools will maintain consenting records to allow participation rates to be calculated.
6. Proportion of student and staff first-order contacts who accept an offer of daily contact testing with LFD devices during the 9-week period of the study. Schools will maintain consenting records to allow participation rates to be calculated.
7. Behavioural outcomes for pupils, parents and staff: acceptability and feasibility of testing, self-reported perceptions and behaviour. Pupils and staff who have been asked to self-isolate to taking part in DCT will be invited to complete a questionnaire on day 7 of their self-isolation or testing period.