Coronavirus: Schoolchildren’s risks of catching and spreading the disease

The government has published advice it received from scientists about the risks of some children in England going back to school on 1 June – after a debate over the safety of its plan.

While the evidence that children become less ill from coronavirus is fairly clear, what’s less clear is how much they might be spreading it to each other and to adults.

Here is what experts understand so far about the potential risks involved in reopening schools.

Are children themselves safe?

Children are at extremely low risk of becoming ill from the virus, so going back to school is not putting them at risk.

Adults – and particularly older adults – are far more likely to be seriously ill and die from complications of the virus.

Across the UK, 0.01% of deaths were people under 15, 1% were aged 15-44 and about 75% were over 75.

The median age of people with confirmed coronavirus being admitted to critical care units in England, Wales and Northern Ireland was 60 as of 15 May, an audit by a research charity suggested – meaning half were older than 60 and half were younger.

But the majority were over 50 and fewer than 10% were younger than 40.

Of all diagnosed cases, children have so far accounted for between 1% and 5%, according to Prof Adilia Warris, a paediatric infectious diseases specialist at the University of Exeter. They have “often milder disease than adults” and deaths have been rare, she says.

There have been some extremely rare cases of children developing an inflammatory syndrome similar to Kawasaki disease and a possible delayed immune response to coronavirus is being explored.

Can children pass on coronavirus?

This is one of the missing pieces of the puzzle about coronavirus and how it spreads.

It is still not clear how infectious anyone is if they have very mild symptoms or no symptoms at all – of any age. To understand this we would need widespread antibody testing to find out who has had the virus across the whole population.

A University College London review of the evidence, based on studies using contact tracing and population screening, suggested children were half as likely as adults to catch the virus.

The government’s Scientific Advisory Group for Emergencies (Sage) said the “balance of evidence” suggested children might be both less likely to catch it and, if they do catch it, less likely to pass it on. But, it said, “evidence remains inconclusive”.

One study looking at cases in Shenzhen in China at the beginning of the year suggested children were just as likely to catch the virus, raising the fear that they were transmitting it without showing any symptoms. But since then studies have had more reassuring findings.

Studies of clusters of infections in family groups across China have concluded, based on contact tracing, that none of the infections were likely to have been introduced by children.

A study of a cluster of infections in the French Alps found a child who tested positive for the virus did not pass it on to any of the more than 100 people they had contact with during the time they had symptoms.

Community studies in Iceland, South Korea, the Netherlands and Italy all found evidence children were less likely to have – or have had – the virus than adults. The Italian region studied tested 70% of its population.

A review of the evidence by a global team of researchers concluded: “The role of children in transmission is unclear, but consistent evidence is demonstrating a lower likelihood of acquiring infection, and lower rates of children bringing infections into households.”

One theory for why children generally have no symptoms or milder ones is that their lungs might contain fewer of the receptors that coronavirus uses to infect cells. But experts say there is not yet any good evidence to support this.

What about staff?

More children in schools means more teachers working, and more parents at the school gates – it’s not yet clear how those extra contacts will affect the spread of infection.

A report on the evidence by Sage said: “It is important to understand the other types of social distancing measures that staff, parents, and students are engaging in beyond the boundaries of the school”.

The group of scientists modelled nine different “return to school” scenarios. On 16 May, Deputy Chief Medical Officer for England Dr Jenny Harries said the government had opted for the one estimated to give the smallest increase in the R number – the measure of how fast the disease is spreading – while still bringing significant numbers of children back to school.

It was reported that in 22 European Union countries where schools were partially reopened, there hadn’t been a significant increase in cases, including among staff. These countries all opened up schools to different extents.

France did report a small uptick in cases after partially re-opening schools.

Why send primary school children back to school first?

Government guidelines say they are starting with Reception, Year 1 and Year 6 children in England because:

• these year groups have important educational needs
• younger children are less likely to become unwell if infected
• older children are more likely to have higher numbers of contacts outside school so pose a greater transmission risk
• older children are typically better able to learn at home

World Health Organization (WHO) chief scientist Dr Soumya Swaminathan says that children are “less capable” of spreading the virus, and are at “very low risk” of getting ill from the disease.

“What we have seen in countries where schools have remained open is that there have not been big outbreaks in schools.”

What do I need to know about the coronavirus?

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• CONTAINMENT: What it means to self-isolate
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