Coronavirus study of children: Most lab-confirmed cases experience symptoms, including some very serious ones

© 2020 Gwen Dewar, Ph.D., all rights reserved

Little girl lying on bed, looking ill and sad. By puhimec / istock

A study of the new coronavirus has been peer-reviewed and accepted for publication in the Journal of Pediatrics. What this study reveal? I've read the pre-publication version released on March 18th. The quick takeaway is this:

  • Some kids (13%) who tested positive for the virus did not experience any symptoms.
  • Most kids (87%) who tested positive did experience symptoms, ranging from mild to severe. Pneumonia was pretty common.
  • Approximately 2.5% of kids testing positive experienced severe or critical illness.
  • Babies and young children were more likely than older kids to suffer severe illness.

How easily did the virus spread?

The study can't help us there.

You might have heard claims that children are less likely that adults to contract the virus. Early data coming from China indicated that confirmed cases among children were disproportionately low.

But, according to the World Health Organization, infected children in China "have largely been identified through contact tracing in households of adults" (WHO 2020).

Outside of this context, there wasn't a major effort to look for coronavirus cases among children.

In addition, the data come from a region that took extreme measures to stop the spread. In this new study, most data concern symptoms experienced after people were in "lock down." We don't know how easily the coronavirus might have spread among children if there hadn't been a lock down.

Finally, the study doesn't offer insights about how easily the virus might be spread from children to adults. That question wasn't addressed.

So what exactly does the study say?

The study (Dong et al 2020) analyzes information about children reported to the China Center for Disease Control by February 8, 2020.

Altogether, the China CDC received reports of 2,143 children either confirmed to have COVID-19  or suspected of having COVID-19.

To be identified as a suspected case, a child had to meet several criteria. These included a combination of risk factors (e.g., being exposed to a confirmed case, or living in an epidemic area) and showing various signs (e.g., symptoms of illness, or an abnormal chest X-ray).

To be identified as a confirmed case, a child had to have a mouth swab, respiratory tract sample, or blood sample tested. And the results had to indicate the presence of the new coronavirus.

Most children in the study fell into the "suspected" category. If all of these children had been tested, it's possible, even likely, that at least some of them would have tested negative. But how many? We can't be sure.

Because of this uncertainty, the researchers did separate analyses for confirmed and suspected cases. And here's what they found.

Outcomes of children with lab-confirmed cases

731 children in this study were confirmed, by lab tests, to carry the virus. Of these 731 lab-confirmed cases, 94 (about 13%) were asymptomatic. The kids weren't showing signs of illness. If their chests were scanned, their lungs looked clear.

The remaining 87% of children who tested positive experienced varying degrees of illness, ranging from mild to critical.

Mild illness. About 43% (315/731) of lab-confirmed cases experienced symptoms of mild illness.

Kids in this category showed one or more of these signs:

  • fever
  • fatigue
  • myalgia (muscle aches)
  • cough
  • sore throat
  • runny nose
  • sneezing

Some of the mild cases experienced only digestive symptoms (nausea, vomiting, abdominal pain, and diarrhea).

Moderate illness. About 41% (300/731)of kids testing positive showed signs of moderate illness.

These kids had pneumonia, frequent fever and cough, and sputum (mucus) in the lungs. Wheezing was sometimes present. Some children didn't experience any of these symptoms, but were determined to have lung lesions (on a CT scan).

Severe illness. About 2.5% (18/731) of lab-confirmed cases experienced symptoms of greater severity, like shortness of breath and lower oxygen levels.

Critical condition. Only 3 children out of 731 confirmed cases ended up in critical condition.

Outcomes for children with suspected (but not confirmed) cases of the new coronavirus.

1,412 children in this study were classified as "suspected" cases. All were symptomatic to some degree. Here's a breakdown in terms of severity:

  • Mild illness: 55% (776/1412)
  • Moderate: 38% (531/1412)
  • Severe: 7% (94/1412)
  • Critical:  Less than 1% (10/1412)

Compared to the lab-confirmed cases, the suspected cases had higher rates of severe and critical illness. But we can't know for sure if these children actually had the new coronavirus. Their symptoms might have been caused by some other, unidentified infection of the respiratory tract.

How did the risk of severe or critical illness break down by age?

Overall -- adding together lab-confirmed and suspected cases -- the researchers calculated these percentages:

  • Under age 1 year: 10.6%
  • 1 to 5-year-olds: 7.3%
  • 6- to 10-year-olds: 4.2%
  • 11- to 15-year-olds: 4.1%
  • 15 and older: 3%

More information about coronavirus

We need to slow down the spread of this virus as much as possible. So please encourage your friends, neighbors, and coworkers to help "flatten the curve."

For more background on the pandemic, and what we can do about it, see my article, "Coping with Coronavirus."

References: Coronavirus in children

Dong Y, Mo X, Hu Y, Qi X, Jiang F, Jiang Z, and Tong S. 2020. Epidemiology of COVID-19 among children in China. Journal of Pediatrics. Prepublication version accessed on March 18, 2020. Download it here: https://pediatrics.aappublications.org/content/pediatrics/early/2020/03/16/peds.2020-0702.full.pdf

World Health Organization. 2020. Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19). Downloaded 3/16/20 from https://www.who.int/docs/default-source/coronaviruse/who-china-joint-mission-on-covid-19-final-report.pdf

image of girl in bed by puhimec / istock

Content last modified 3/18/2020