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Children do not appear to be COVID-19 'super-spreaders'

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Payne, Elizabeth
Publication Date: 
26 May 2020


Children are neither highly susceptible to COVID-19 nor the super-spreaders people feared they might be, according to mounting research.

Despite some rare, but serious, complications, children in Canada and around the world are the least affected by COVID-19.

“There is a lot we don’t know yet, but what we do know is that there are fewer children infected compared to adults and the children are less severely affected if they are infected,” said CHEO infectious disease physician Dr. Nicole Le Saux.

The lighter impact of COVID-19 on children and teens was unexpected, she said.

“It has surprised everybody. The good thing is at least there is one group that isn’t getting hit so much.”

There have been cases of severe illness among children reported around the world. And doctors in Canada and elsewhere are on alert for cases of a rare hyper-inflammatory syndrome that appears to be related to COVID-19, even among some children who tested negative for the disease. There have been reports of severe illness and even death from the syndrome among some children in the worst-hit parts of the world.

But the overall impact on children has been less severe than on adults, something doctors don’t entirely understand.

Across Canada, children under 19 made up just 5.69 per cent of all confirmed COVID-19 cases as of May 25. A total of 34 children have been hospitalized for treatment related to COVID-19 in Canada and just two of those children required intensive care.

More than 6,500 Canadians have died from the novel infectious disease so far, none of them children or teens under 19.

The reason the impact on children has been so surprising is that it does not follow the typical pattern of seasonal influenza in which children are often severely affected and can act as “super-spreaders,” said Le Saux. With seasonal flu, schools often become epicentres of infection and children bring it home to their parents and grandparents.

“It does not appear that way so far with COVID,” said Le Saux. “The epidemiology appears different.”

Evidence being gathered around the world indicates that family clusters rarely begin with an infected child. And only a small minority of children become infected even when COVID-19 is in the household, according to research from Wuhan.

In addition, far fewer asymptomatic children test positive for COVID-19, compared to adults. Regions that have tested the entire populations — including in Iceland and part of Italy — found up to 2.6 per cent of asymptomatic adults were infected with COVID-19, but no asymptomatic children were infected. Whether that is because children are not infected or because their viral load is so low that they test negative, health officials do not know.

As with all aspects of the novel coronavirus, there are many questions still to be answered about how it affects children, said Le Saux.

“Why children aren’t infected as often is a really good question. Hopefully, there will be lots of research and we will figure it out.”

Some research has focused on children’s lungs. There are fewer receptors, which the virus attaches to, in a child’s lung than in an adult’s.

Understanding the impact of the pandemic on children has broad implications for better controlling the pandemic. Getting children back to school and daycare is key to reopening economies. Around the world, some 900 million children have missed some school since mid-March.

Those decisions are ultimately up to public health experts, politicians and parents. But the growing body of data about COVID-19 and children should be considered, said Le Saux.

“There are unintended consequences to school closures on mental health and social inequality.”

Early data suggests that where schools have reopened, they have not become centres of COVID-19 outbreak.

In Australia, hundreds of students and staff were tested after a handful of students and staff tested positive for COVID-19. The infection did not spread despite the contact at school.

“It suggests that closeness of contact wasn’t enough to get other people infected.”

It will be difficult to keep children physically distant in school and especially daycare, she said, but it is a question of balancing risk and taking every precaution. Even then, she conceded, not all parents will be willing to accept any risk that their children could get COVID-19.