Experts: Middle, high school youth spread coronavirus as much as adults

Republished with permission from Madison365

Children of middle- and high-school age are probably just as likely to spread the novel coronavirus as adults, but it’s uncertain what effect opening schools could have on the prevalence of the virus in the wider community, three experts said in interviews this week.

That uncertainty looms over school districts’ decisions to open this fall for in-school instruction, or conduct all learning at a distance over the internet, or implement a hybrid approach. It also looms over individual families as they make schooling decisions for their own children.

Madison365 spoke with three local experts: Public Health Madison Dane County data analyst Brittany Grogan, University of Wisconsin infectious disease epidemiologist Dr. Ajay Sethi, and Dr. Malia Jones, an associate scientist in health geography at the Applied Population Laboratory at the University of Wisconsin. Their verdicts were consistent: 

• Children can and do get infected and sick from the coronavirus
• Children of all ages get infected less often than adults
• Infection leads to serious illness in children far less often than in adults
• Children can and do spread it
• Younger children spread it less than adults do
• Older children spread it just as much as adults do
• At least part of the reason children get it and spread it less is that they haven’t been in school

Grogan said she analyzed data regarding school-aged children — those aged 5 to 18 — from the beginning of the pandemic in March through July 11. In that time period, 205 cases appeared in school-age children in Dane County. Of those, 60 percent showed symptoms, and three percent had to be hospitalized. Both of those measures are considerably lower than in adults: 75 percent of people 19 or older exhibited symptoms and eight percent were hospitalized.

“Kids are much more likely to get it themselves from someone in their household. Fifty-five percent of the youth were infected by having household contact with someone else who was infected compared to 27 percent for adults,” Grogan said. “And we do have several documented cases of a parent who works at a workplace with an outbreak, and that parent got infected and then subsequently their child got it from them.”

Jones echoed the fact that cases in children tend to be less serious than those in adults.

“Children who get infected with COVID-19 are much less likely to have severe outcomes than adults or even older. And there seems to be an age effect there. So the younger children, very, very rarely have a hospitalization or death from COVID-19. And even older children, teenagers, are much, much less likely than adults to have a severe outcome.”

Sethi said it’s likely that children under 10 get sick less often because their cells have fewer ACE-2 receptors, the proteins that allow the coronavirus to grasp onto a cell. 

“As you grow, you produce more ACE2 receptors. So literally the virus doesn’t have as much binding sites when you’re really young compared to when you’re older,” he said. 

But children can still transmit the virus — especially older children.

“Certainly I think that in terms of reopening schools, the potential for kids to infect one another and then carry the germs home to their families is real,” Jones said.

“The science has kind of been towards the older you are among that age (range from 0-18), the more likely you’re going to transmit the virus like another adult,” Sethi said. “And most people are kind of putting 10 years and up as being more or less the way adults transmit the virus.”

“There is a big study that’s from South Korea contact tracing that suggests that young kids were very, very rarely involved in a localized outbreak, but teenagers were pretty much the same as adults,” Jones added. 

That means it might make sense to think of middle- and high schools differently from elementary schools.

“There’s merit to having … age-based policies, or grade-based policies,” he said. “Whether you meet in person or not. But this is still kind of an experimental period because it’s not like you can look back on the spring and say, this is what happened because schools were open because they weren’t opened, they were closed.”

Jones also noted that the understanding of how children contract and transmit the virus is limited because of the measures taken to protect them.

“There are a number of limitations about what we know about kids and kids’ risks. And one of them is that we have not observed kids in sort of the thick of a pandemic doing their normal activities,” she said. “Schools shut down relatively early on. And so yeah, kids have had lower exposure since this all started, than we would expect them to in the school settings.”

Both Sethi and Jones said what’s happening in the community around the schools is important to consider when deciding whether to open schools.

“Schools can safely open, actually any place can safely open, if you bring community spread down to really sporadic levels. I mean, maybe a month and half ago, we were at one to two percent positivity in Madison. Those were the days. If only we were able to sustain that and maybe continue that downward trend,” schools might be able to open fully, Sethi said. “And it’s not a knock on us. It’s happening everywhere.”

The average daily positive test rate for Dane Count as of July 13, the most recent date available, was 5.5 percent.

Sethi said in addition to an age-based approach, it can make sense for different localities to enact different policies suited to different local situations.

“Once when it gets down to the local level, it gets adapted to what parents, teachers, the community thinks is best,” he said. “Also using sort of science and evidence. But yeah, so I agree it’s local, but I don’t think that absolves the responsibility of anybody higher up. I mean, everybody has a role to play.”

But that doesn’t mean a local community should act as if everything is normal just yet.

“The reality is, if you live in a county where there’s very few cases and you conduct life and business as usual, that’s exactly what we were doing in February and look what happened,” he said. “Now the virus did transmit most likely in the higher density populations. So exceptionally rural places can escape widespread transmission. They’re more likely to escape widespread transmission than a densely populated city. And that’s just how respiratory viruses work. I don’t think there’s complete protection, but I think there’s also something to be said for prevention. If you don’t have cases, do what you need to do to keep it that way.”

In any case, we will know more later in the fall.

“We will learn a lot from those schools” that open, Jones said.

Sethi also acknowledged the potential downsides of virtual learning, including disparities in internet access and ability for parents to stay home.

Madison, Sun Prairie and Middleton-Cross Plains school districts have announced that they’ll begin the school year through distance learning, at least for the first quarter. In Mt. Horeb, half of the students will attend Mondays and Tuesdays, and half Thursdays and Fridays. Other school districts in Dane County are still considering options.