Daily testing of pupils who have been in contact with someone with Covid-19, rather than isolating whole groups, may be just as effective in controlling transmission in secondary schools, a study suggests.
Research by the University of Oxford estimates that daily Covid-19 testing in schools – as an alternative to the current 10-day contact isolation policy – can reduce coronavirus-related school absences by 39%.
Findings suggest only a small percentage (1.5-1.6%) of pupils and staff tested positive for Covid-19 after close contact with a case in school or college.
Around 200 secondary schools and colleges across England took part in a trial. One group followed the national guidance of quarantining contacts of positive cases for 10 days, and the other allowed contacts to take rapid lateral flow tests daily at school over a week instead of isolation.
Researchers found there was no evidence that the rate of students and staff developing Covid-19 with symptoms was different in the group doing daily testing compared to the group isolating at home.
The findings come after Government figures show that more than one million children in England were out of school last week for Covid-19-related reasons – the equivalent of around one in seven (14.3%) – with 934,000 children self-isolating due to a possible contact with a Covid-19 case.
Current rules say that children have to self-isolate for 10 days if another pupil in their bubble – which can be an entire year group – tests positive for Covid-19.
Secondary school children and parents in England have been encouraged to test at home, twice a week, over the summer term.
The study analysed data from more than 200,000 students and 20,000 staff between April and June 2021. It invited close contacts to provide a research PCR test for Covid-19 on day two and seven following contact, in order to determine how many close contacts became infected.
Researchers have estimated that there were slightly fewer infections among pupils and staff when daily Covid-19 testing was used in schools, compared to among the group who were isolating at home for 10 days.
The findings suggest that 1.5% of the contacts who attended school to do daily lateral flow device tests tested positive or indeterminate for Covid-19, compared to 1.6% of students and staff staying at home.
Bernadette Young, clinical lecturer in infectious diseases at the University of Oxford and an investigator on the study, said they had expected daily testing to improve transmission control due to the “social penalties” attached to the 10-day self-isolation policy.
Dr Young said asking pupils to carry out asymptomatic testing twice a week, as well as naming friends they have been in close contact with, could prevent secondary students from being “more upfront”.
She said: “Now if the consequence of you testing positive is that all your friends are put in isolation, there’s a social penalty that goes with that.
“And so the hypothesis was, or the theory was, that if that penalty is lessened because your classmates will still be allowed to attend school, your motivation to testing will change.”
Dr Young added: “By offering daily testing, you identify more of those who are truly positive and isolate specifically those who are positive, and they’re more likely to withdraw from [social] mixing and decrease the number of infectious cases present in the wider context. So it makes sense that it could happen.”
The study, which was sponsored by the Department of Health and Social Care and supported by the Department for Education and Office for National Statistics, suggests that 1.8% of available school days were lost due to Covid-19 in the group who continued the self-isolation policy, compared to 1.5% of available school days being lost in those who took part in daily testing.
In the preprint study, which has yet to be peer-reviewed, researchers estimate that school-based contacts taking part in daily coronavirus testing can reduce Covid-related school absences by 39%.
Tim Peto, professor of medicine at the University of Oxford and principal investigator on the study, advised policymakers to use the study to think about transmission in the workplace compared to schools – and whether employees in other workplaces would be “enthusiastic” about testing.
He said: “Our findings indicate that there is no significant difference in Covid-19 transmission between schools where bubbles were sent into home isolation versus those where daily contact testing was implemented instead.
“Infection rates in the close contacts were low in general, and there was little difference between those who went to school following a negative lateral flow test and those who were isolating at home.”
Earlier this month, Education Secretary Gavin Williamson told MPs that secondary schools and colleges will be asked to provide two on-site tests to their students at the start of the autumn term.
He said regular home testing will continue until at least the end of September.
But from August 16, children in England will only need to self-isolate if they have tested positive for Covid-19.
David Eyre, associate professor at the University of Oxford, and an investigator on the study, said: “Daily testing was able to identify most of the small number that do [become infected], which allowed them to safely isolate at home, while allowing the large majority of other students and staff to remain in school.
“Reassuringly too, rates of infection in school staff were lower than those in students.”
Susan Hopkins, chief medical adviser for NHS Test and Trace, said: “This is a major breakthrough, showing that daily contact testing can keep young people in classrooms instead of making them isolate at home.”
She added: “We’ve been trying to find safe alternatives, and this study gives us evidence of safe alternatives to isolation for school contacts.
“So far, self-isolation has been one of the most effective tools at our disposal against Covid-19 – stopping isolated cases from becoming major outbreaks. To have another potential tool like this is great news.”
A Government spokesperson said: “Throughout the pandemic we have followed scientific and medical advice, putting in place protective measures such as self-isolation following contact with infection to keep our schools and wider communities safe, while prioritising students’ attendance at school and college because of the benefits of face-to-face education for development and wellbeing.
“As we have moved cautiously through to step 4 the road map, schools now no longer need to operate a bubble system, and from August 16 pupils will not need to self-isolate should they come into contact with a positive case, in line with the position for wider society.
“Where children have needed to isolate, they will have been offered immediate access to high-quality remote education.”