Coronavirus and kids — how dangerous is it, can they spread it, and how much do school closures help?

(Jeremy Harmon | The Salt Lake Tribune) The playground at Hawthorne Elementary in Salt Lake City is taped off so it can't be used as schools around the state remained closed because of the coronavirus pandemic on Monday, March 23, 2020.

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The coronavirus is killing tens of thousands of people who lived in nursing homes and tens of thousands more who had underlying health conditions. Many of the warnings are rightly focused on protecting people who are older than 65.

But what about kids? I’ve received emails from readers who want to know how COVID-19 affects children. So let’s break down the current state of the research — with a side helping of what it means for schools.

Can kids get COVID-19?


Do kids get it at the same rate as adults?

Most evidence says no.

Age reporting is inconsistent from location to location, but take New York City as an example: Out of its 170,534 cases so far, 4,088, or 2%, came from those under 18 years old. To put that in perspective, 20.9% of NYC’s population is under 18. That data roughly matches an early April Centers for Disease Control and Prevention study that found 1.7% of cases in the United States involve those under 18 — 22% of the U.S. population is under 18.

That CDC study also showed that the rate was skewed toward older kids. Researchers found that 32% of pediatric cases happened in children between 15 and 17, while 27% happened in the 10 to 14 age group, 15% were found in children between 5 and 9, 11% in those 1 to 14, and interestingly, the remaining 15% were infants less than 1 year old.

As for Utah, we have both more kids, and more cases among those kids, than the rest of the U.S.

As of Tuesday, Utah has 5,449 total cases and 213 have been kids between 1 and 14 years old, which is about 4%. And 22% of Utahns are in that age range — which you’ll notice is annoyingly a different age range than most of the nation’s coronavirus reporting, which uses the 0 to 17 definition. There were 26 cases from infants under 1 in Utah.

A reasonable question: Are there fewer coronavirus cases in kids because of differences in testing or symptoms between kids and adults? A reasonable answer: Most studies still show the disparity even when there is widespread testing.

For example, when Iceland tested a random sample of its population, it found zero kids tested positive out of 848, when among the rest of the population, 0.8% had it. Vo, Italy, had a similar thing happen: 2.6% of its adult population had it, but none of the 217 kids under 10, and 3 out of 250 (1.2%) 11- to 20-year-olds had the disease.

OK, one final way to look at it: If an infected adult brings the coronavirus into a home, are the kids and adults who live there equally likely to get infected themselves? One study in Shenzhen, China, found that kids and adults were about equally likely to contract the virus. However, a study in Guangzhou showed that the infection rate for kids in household transmission scenarios was less than half that of adults.

Studies sometimes contradict. Science gets messy sometimes.

How dangerous is COVID-19 for kids?

Children are exceptionally unlikely to die from COVID-19. In NYC, for example, of those 4,088 cases found in children, six have died. All six had underlying conditions. In the 2,572 CDC cases in that early April study, there were three deaths.

There has yet to be a death of a child due to coronavirus in Utah.

That’s not to say COVID-19 in kids can’t be rough, though: A small but significant percentage of kids are hospitalized. In NYC, 7% of 0 to 17-year-olds have been hospitalized. In Utah, 2% of the cases for 1- to 14-year-olds were. The CDC study splits the difference with 5%.

It’s hard to know how many kids get through this without showing any symptoms. Estimates range from 13% to 32%, though because we don’t have wide-scale antibody testing, we really don’t know. It could be significantly larger than that. Over 56% of pediatric cases sampled by the CDC got a fever, 54% got a cough.

Interestingly, there’s preliminary research that indicates that kids with asthma and allergies might actually be less susceptible to COVID-19, because their bodies have less of the receptor that the coronavirus uses to attack cells. The National Institutes of Health announced Monday that it is beginning a study to find out more about this and other topics. Obesity, though, still seems to make children more susceptible.

Finally, there’s a very small percentage of kids who seem to be suffering a pretty gnarly and confusing set of symptoms that has been linked to COVID-19 in its late stages. Essentially, our first guess is that the autoimmune response in these kids is backfiring and causing real problems — like toxic shock — that send them to the intensive care unit. It was first noted in the United Kingdom with “more than a dozen” kids last week, and now there are 15 kids with these symptoms in NYC. Health officials there issued a bulletin Monday; none of them has died.

Can kids spread the coronavirus?

They can, but for whatever reason, it hasn’t seemed to happen as often as you’d expect.

Kids are usually master disease spreaders. They’re in constant close contact with huge numbers of other kids. They have a tendency to be pretty careless with their coughs, sneezes and snot. They’re on the ground all the time. Then, they bring all that home and give diseases to the rest of their family.

So when one Chinese study looked at avian flu (H5N1) transmission within households, it found that 54% of them had a child as Patient Zero, who then spread it to the other members of the family.

That same study then looked at coronavirus houses. Only 9.7% of those had a child as Patient Zero.

The Dutch did a similar study of 54 households. Zero of them had a child as the first patient with coronavirus.

Finally, take this 9-year-old from Britain who caught the coronavirus in February while at a French skiing chalet. He actually ended up testing positive for three viruses: the coronavirus, a picornavirus and influenza A. But it turned out that his two siblings caught the flu, one caught the picornavirus, and neither the coronavirus. And when they tested 73 kids at the schools he went to — while he was symptomatic! — all of them tested negative for the coronavirus, while 64% of them had one of the other viruses.

We don’t have a mechanism that explains why this is happening. In particular, kids have just as much viral load of coronavirus in their throats as adults do, so their coughs and sneezes should be just as effective at spreading the disease when they have it.

With that in mind, some believe the data that shows lesser spread from children is just circumstantial. Early transmission mostly happened via adult travelers. Most countries closed schools very early, so maybe kids just didn’t get the chance to catch it from other kids. Maybe the British 9-year-old just got lucky.

Or maybe there’s something real going on here, and kids are less likely to spread the disease. Truthfully, we may not really find out until schools reopen.

How much does closing schools help?

I was surprised to find an abundance of research in answering this question, because it seems that it’s been considered numerous times for influenza outbreaks. These studies have essentially asked the pertinent question “For what type of viruses does it make sense to close schools?”

One systematic review of the research found that, on average, the peak of the epidemic caused by flu viruses was reduced by 30% after school closure. Another review of real-life school closures found that the timing of the closure was especially important, with closures much more effective if implemented relatively early. Given this, you can understand why we closed schools nearly immediately.

But the research also indicates conditions where school closure is less effective, and it appears that the coronavirus may be the kind of virus where it doesn’t make a ton of sense in a vacuum. For example, the second review of real-life closures found that closing schools significantly reduced the number of child cases, but not adult cases, in a community.

And a third review of the research found that school closings were “usually predicted to be most effective if ... transmissibility was low (e.g. a basic reproduction number <2), and if attack rates were higher in children than in adults.” That’s the opposite of the set of conditions we have in this pandemic.

One recent study published in the Lancet sought to tackle this question for COVID-19 in particular. It noted that studies didn’t show that school closures helped in the original SARS epidemic in 2003 and were of mixed results in the MERS coronavirus epidemic. With the set of conditions for this novel coronavirus, researchers estimated school closures alone would prevent 2% to 4% of deaths.

I don’t want to minimize 2% to 4% of deaths: With a baseline 68,000 deaths that we’ve had in America, that’s 1,360 to 2,720 deaths we’ve prevented. That is important! Balancing those interests with the interests of the tens of millions of kids who are home from school is beyond my pay grade.

What issues are there to think about when opening schools?

A few countries — Denmark, Japan, Norway, China, Israel and Taiwan — have looked at the above research and decided to open schools. This Insider article did a great job of showing all of the different changes that have been made in these locales to open up schools now. To sum:

  • Desks are stationed 6 feet apart.

  • Parents aren’t allowed inside school buildings — no PTA meetings, etc.

  • Staffers who are over 65 or who have underlying conditions are asked to stay home.

  • In Japan, Taiwan and China, kids have their temperatures checked before school.

  • In Denmark and Norway, classes are held outside whenever possible.

  • In Denmark, kids have to wash their hands every hour. In Taiwan, they have to wear masks.

  • In Denmark and Norway, they’ve split classes up to be groups of about three to 10 kids, rather than their previous average class sizes of about 20.

Kids also aren’t allowed to congregate in big groups during recess, nor are they allowed to touch one another. To compensate, the Danish kids have invented “shadow tag” — rather than tagging by touch, now tagging the other kid’s shadow is enough to complete the tag.

To be honest, returning to school seems like it’s working relatively well in these countries.

And yet, when you look at that list of changes, it’s nearly impossible to imagine any of that — beyond shadow tag — happening in America. Utah is a good example: our average class size is 27.4 students in elementary schools and 31.5 students in high schools. How are you going to split classes into groups of three to 10? Maybe you stagger schedules, but getting 31.5 down to 10 means school only once every three days. That may not be worth it, quite frankly.

That’s just one of a seemingly unending list of questions:

  • How are you going to keep desks 6 feet apart in small classrooms, many of which were in temporary facilities due to overcrowding already?

  • Where would outdoor classes happen in urban schools?

  • How do you handle the deficit of teachers who have to stay home — especially if obesity (40% of American adults are obese) is considered a preexisting condition? Also, do they get paid?

  • How do you handle the kids who want to stay home because their family is at risk?

  • How do you handle assemblies, graduations, sports, performances and other large groupings? Are they all just canceled?

  • What do you do with those angry parent types who won’t react well to their kids’ temperature being scanned or want to storm in the building they’re not allowed in?

This isn’t a situation where you want the perfect to be the enemy of the good — opening up schools would help literally hundreds of millions of Americans in one way or another. And there’s a reasonable, if controversial, argument for opening schools if you can take the necessary precautions.

But due to the, ahem, “quirks” of our public education system, we’re probably in a situation where it’s just impossible to open right now, especially in Utah. And they won’t. Utah has already decided to close schools for the remainder of the academic year.

Interestingly, one Idaho private school has decided to open its doors for its 730 students after polling parents. School officials will stagger schedules, and they estimate that 20% to 40% of kids will choose to stay home, which they say is enough to maintain social distancing. They’re also encouraging kids, but not requiring them, to wear masks. Their planning is apparently sufficient enough to get the approval of their health department.

Thousands of schools and school districts will be watching the Idaho experiment, as well as a few other private schools around the country that are sure to join in the coming weeks. We’ll learn a lot from those schools about reopening successfully, likely in the fall.

But for now? Kids, the least susceptible among us, are staying home.

Andy Larsen is a Tribune sports reporter who covers the Utah Jazz. During this crisis, he has been assigned to dig into the numbers surrounding the coronavirus. You can reach Andy at alarsen@sltrib.com or on Twitter at @andyblarsen.