Reopening schools 'could trigger serious second peak' if test and trace isn't improved, scientists warn

The reopening of schools has been described as an “absolute priority” amid concerns students are missing out on critical education and social interaction.

In an attempt to control the coronavirus outbreak, the UK government shut nurseries, schools and colleges on 20 March.

Critics argued children rarely become seriously ill with the infection, with some evidence also suggesting they are half as likely to catch it in the first place. It is feared that while virtual lessons enabled some youngsters to keep up their schooling, those from less privileged backgrounds will have missed out.

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Housing secretary Robert Jenrick has said schools throughout the UK will be up and running in September, with the gates previously only being open to select year groups.

This is despite the easing of other lockdown measures being put on hold as a rising number of cases are being reported in England.

Scientists from University College London (UCL) have warned allowing youngsters back to school could trigger a dreaded second peak as soon as December unless the much-criticised track and trace system is “scaled up”.

‘Serious second peak’ without scaled up test and trace

“Our modelling suggests that with a highly effective test and trace strategy in place across the UK, it is possible for schools to reopen safely in September,” said lead author Dr Jasmina Panovska-Griffiths.

“However, without sufficient coverage of a test-trace-isolate strategy the UK risks a serious second epidemic peak either in December or February.

“Therefore, we urge the government to ensure test-trace-isolate capacity is scaled up to a sufficient level before schools reopen.”

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Under the existing system, anyone in England with symptoms – fever, cough, or a loss of taste or smell – should arrange a coronavirus test.

If positive, contact tracers will ask the patient for the details of those they have been close to. These individuals are then told to isolate entirely at home for 14 days.

The Scientific Advisory Group for Emergencies (Sage), which advises the government, has said 80% of contacts must self-isolate for the system to be effective.

Overall, 83% of the contacts provided were reached between 28 May – when it launched – and 22 July. This is declining, however, with the number contacted in the past few weeks being below that threshold.

Schools reopening ‘goes hand in hand with adults returning to work’

Jenrick has insisted schools “will be safe in September”, stressing remote learning “isn't a substitute” for face-to-face education.

While many are undoubtedly keen to return to normality, England’s chief medical officer Professor Chris Whitty has warned the country is “near the limit” when it comes to reopening society.

Professor Graham Medley, chairman of the Sage sub-group on pandemic modelling, has suggested pubs – which reopened in England on 4 July – may have to shut as a “trade-off” to getting children back in the classroom.

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The UCL scientists have suggested, however, a more effective test, track and trace system could be another solution.

After modelling six different scenarios of schools reopening, the team found a second wave could be avoided if testing increased so that 59% to 87% of those with symptoms were swabbed for the virus.

Among those testing positive, the scientists modelled how things would play out if 68% of their contacts could be traced.

They found three-quarters (75%) of those with a symptomatic infection would need to be diagnosed and isolated if schools return full-time in September.

If schools were to open part-time, the diagnosis and isolation rate could fall to 65%, according to the scientists.

Assuming only 40% of contacts could be traced, 87% and 75% of symptomatic cases would have to isolate to allow schools to operate full or part-time, respectively.

Not all infected individuals develop symptoms, however, they are thought to still spread the virus.

Should diagnoses and contact tracing fall below these levels across the UK, the reopening of schools in September combined with the easing of lockdown means a second wave would likely peak in December.

A part-time reopening would lead to a peak in February 2021, the results – published in The Lancet Child & Adolescent Health – suggest.

Experts have repeatedly expressed concern of infection rates rising during the UK’s winter, when seasonal flu is also circulating.

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Continual lockdown easing combined with insufficient test and trace could even result in a second wave two to 2.3 times bigger than the first, which hit the UK around March, according to the scientists.

The results remained the same when the team modelled children being as infectious, or half as much, as adults. The extent to which youngsters pass on the virus has been debated.

“It’s important to note our model looked at the effects of school reopening alongside the loosening of the restrictions across society, as school reopening is likely to go hand in hand with more adults returning to work and other relaxed measures across society,” said Dr Panovska-Griffiths.

“Therefore, our results are reflective of a broader loosening of lockdown, rather than the effects of transmission within schools exclusively, suggesting an effective test–trace–isolate offers a feasible alternative to intermittent lockdown and school closures to control the spread of COVID-19 [the disease caused by the coronavirus].”

‘No quick fixes’ to outbreak

Study author Professor Chris Bonell from the London School of Hygiene & Tropical Medicine (LSHTM) stressed the results should not put officials off reopening schools.

They should instead be a “loud call to action to improve the infection control measures and test and trace system so we can get children back to school without interrupting their learning again for extended periods of time”, he said.

A second study that tracked the spread of the coronavirus in 25 Australian schools between January and April found the risk of children or staff transmitting the infection was “very low” when contact tracing and other measures were in place.

Twenty-seven students or teachers went to a school or nursery while infectious, but only 18 (1.2%) additional people went on to catch the infection out of their combined 1,448 contacts.

“Both studies give potential options for keeping schools open and show the clear importance of adequate contact tracing and testing,” said Professor John Edmunds, from the LSHTM.

“However, many questions remain, including whether there are age-related differences in susceptibility and the likelihood of transmission between children and adolescents.

“There are no quick fixes to this terrible pandemic. However, it is becoming increasingly clear that governments around the world need to find solutions that allow children and young adults to return to full-time education as safely and as quickly as possible.”

Other experts largely praised the “highly informative and timely” studies.

Professor Matt Keeling from the University of Warwick pointed out, however, “the [UCL] authors ‘assumed if schools were to reopen full time, the transmission probability in community settings would be 90% of its pre-lockdown value’.

“Therefore the paper actually models the impact of the UK removing almost all of its lockdown measures including the re-opening of schools,” he said.

“Under such considerations it is unsurprising a large second wave is predicted.”

The UCL team also did not specify how the test, trace and isolate system could be scaled up, added Professor Keeling.

“This paper therefore is an important addition to the debate around how the country can safely reopen,” he said.

“Other mitigation methods, such as closing some non-essential leisure activities such as pubs, are more straightforward although have a larger impact on the economy.”

Dr Thomas House from the University of Manchester added the assumptions used in the models make the results “plausible but potentially pessimistic scenarios, rather than precise predictions”.