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PHE denies it has evidence that older pupils pose Covid infection risk

<span>Photograph: Oli Scarff/AFP/Getty</span>
Photograph: Oli Scarff/AFP/Getty

The government has moved to quell anxieties over its plans to get children back to school by denying it has unpublished evidence that older pupils are more likely to carry coronavirus infections back to their communities.

An as yet unpublished study by Public Health England (PHE) is thought to have signalled a difference between primary school and secondary school children. Older children are more likely to get Covid-19, although nearly all children and young adults suffer only mild symptoms.

Reports on Tuesday claimed that the study had also found that older children were more likely to pass the virus on. Tough social distancing restrictions would be imposed on secondary schools, said the reports, running counter to Gavin Williamson’s assertion on Monday that a return to full-time schooling carried few risks.

PHE later said in a statement that the reports were incorrect. “Parents can be reassured that to maximise safety in schools, an extremely stringent system of controls has been advised by PHE and is published in DfE guidance,” said Viv Bennett, PHE’s chief nurse. “Evidence so far indicates that schools do not appear to be a primary driver of coronavirus infections in the community.

“Globally, children and young people have been found to experience coronavirus asymptomatically or as a minor illness. Age remains the biggest determinant for severe illness, and complications in children and young people are extremely rare.

“Reports that PHE has recommended tougher rules for older children are incorrect.”

The report is likely to show that most children are infected with coronavirus at home, not at school. Higher rates of infection among school children are driven by large numbers of cases in their community, not the other way round.

The health minister, Edward Argar, said on Sky News: “I think we should be cautious about reading too much into that work in progress; it’s important work, but it isn’t complete yet.

“On the basis of the work that has been completed and those international comparators, we are confident that children and young people are much less at risk from this disease and from passing it on than other adults more broadly in the community.”

PHE’s sKID study was carried out in 20,000 schools in the last weeks of June. Children had weekly nose swabs for the virus or a series of pinprick blood tests to establish whether they had had it in the past. The full study will not be published for months, but preliminary results are expected soon.

It is expected to conclude that the youngest children are least likely to get Covid-19 or to experience severe symptoms. Older children and young adults contract it more often, but in a mild form compared with their elders. Whether they easily infect other people is still not clear.

Other real-world evidence suggests there is only a relatively low risk that children in school transmit Covid-19, said the president of the Royal College of Paediatrics and Child Health, who believes continuing to keep them out of school will cause real harm. Prof Russell Viner contrasted the “quite reassuring” findings from schools where children had gone back or were never sent home with the sometimes alarmist messages from modelling studies.

“It’s a balance between observed data – what we’ve seen happen, which I think is quite reassuring – and theory. We can wind ourselves up to be very worried on the basis of theoretical risks,” he told the Guardian.

Viner said there was some evidence that those over the age of 12 could be more susceptible to infection than younger ones, and possibly as susceptible as adults. But, he said, children get the disease very mildly on the whole and only 20% show any symptoms. The unanswered question is to what extent children then transmit the infection to teachers, their families and the wider community – and that’s where the real-world studies are important, he said.

“I think we should be reassured by the admittedly quite scarce and incomplete data we have. But I think we’re in situation of uncertainty. And we either sit and damage our children a whole generation further, or we act on what is a small amount of reassuring data,” he said.

He suggested people would say there were problems with the real-world data on school transmission, arguing that it came at a time when schools were largely closed. “The answer is, some of it did, but I think it’s overstated. Quite a bit of the data came from when schools were still open,” he said.

Prof Kristine Macartney from Sydney University, lead author of the most comprehensive study of school transmission so far, published this month in the Lancet Child and Adolescent Health, found that there was little difference between primary and secondary schools in New South Wales, Australia, where most have remained open.

“But I think it’s quite plausible that you could see greater transmission in the older years,” she said. The disease affects the under-10s less than it does teenagers, she said.

Between 25 January and 10 April, across more than 3,000 schools, the study found transmissions in 10 high schools and five primary schools, involving 12 children and 15 adults, but only five secondary cases within schools in total – three children and two adults.

“Overall, in the schools we’ve continued to monitor since the very beginning of the year, we have not seen much secondary transmission, but by and large, that’s been in the context of being able to control transmission in the community.”

Viner said it was important to keep transmission as low as possible in the community. “We need the research in place, and secondly we need the test-and-trace system … robust across the whole country. But we need it to work very closely with schools. There needs to be a strong tie-in of schools to the local test-and-trace systems.”