Incidence of long COVID 'strikingly low' in children, Alberta researchers find

Lead author Lyndsey Hahn said the study is only
Lead author Lyndsey Hahn said the study is only

New research from the University of Alberta has found a "strikingly low" incidence of long COVID among children ages eight to 13 who contracted COVID-19.

"It's reassuring that in our study we found that most kids resolve symptoms within two weeks," said Lyndsey Hahn, a postdoctoral fellow in the pediatrics department of the University of Alberta's faculty of medicine and dentistry.

Hahn is lead author of the study, Post-COVID-19 Condition in Children, which was published this month in the journal JAMA Pediatrics.

Only one child in a study group of 271 developed long COVID after a COVID-19 infection, the study found.

"The incidence of [long COVID] in this study was strikingly low," the authors say in a research letter.

Hahn, however, cautioned in an interview that the study is only "a tip of the iceberg" and that more research is needed to better understand long COVID in children.

Between August 2020 and March 2021, researchers from the U of A and the Women and Children's Health Research Institute in Edmonton recruited a study group of 1,026 children ages eight to 13.

Parents provided consent and tracked their children's symptoms. The children were followed for 76 weeks.

At the time they were recruited for the study, none of the children had been infected with the virus that causes COVID-19.

University of Alberta researcher Lyndsey Hahn is the study's lead author.
University of Alberta researcher Lyndsey Hahn is the study's lead author.

University of Alberta researcher Lyndsey Hahn. (Submitted by Lyndsey Hahn)

Of the 1,026 children, 572 did not test positive for COVID-19 during the study period while 454 did.

The researchers focused on a group of 271 children who tested positive for COVID and for whom there was sufficient data to determine the presence of long COVID.

Of that group of kids, only one — or 0.4 per cent — met the World Health Organization's definition of the condition.

That child's symptoms resolved near the end of a 14-week post-infection followup period, the study authors noted.

Common symptoms of long COVID include fatigue, shortness of breath and cognitive dysfunction, although the WHO says more than 200 different symptoms have been reported.

The WHO definition of long COVID says it involves "continuation or development of new symptoms three months after the initial SARS-CoV-2 infection, with symptoms lasting for at least two months with no other explanation."

Because the participants signed up for a study before they got COVID, scientists were able to see if they had any symptoms of an infection before they got COVID itself.

Sometimes a child had the dual misfortune of getting one respiratory infection first, such as  common flu, and becoming ill with COVID immediately afterwards.

In such cases, it took longer for children to recover from their symptoms completely, Hahn said.

That finding is a cause for concern, said Dr. Candace McNaughton, a research scientist and an emergency physician at Sunnybrook Health Sciences Centre in Toronto. McNaughton was not involved in the study.

"Having a child who is sick with a fever or headache for four weeks or more is a big deal, even if it does not qualify as post-COVID condition," she said.

"My take-home from the study is that a large proportion of children have symptoms that could impact their schooling or work for parents for a month, which is a big burden for parents and families to bear," she added.

McNaughton said the Alberta study is "another piece in the very large puzzle that we have right now with regards to the long term effects that COVID may have on children."

These long-term effects, McNaughton said, may include having difficulty speaking or remembering things, high heart rate that lasts for several months after getting the infection, and Type 1 diabetes.

"There's enough evidence for me as a mother, and a physician, and as a researcher to say, this is a virus I'd like to avoid," McNaughton said.

Dr. Tehseen Ladha, an assistant professor in the pediatrics department at the U of A, praised her colleagues for conducting the study. Ladha was not involved in the research.

"I think long COVID is an area that we know so little about, and to see researchers and academics really focusing on it from my home university is really uplifting," Ladha said.

In her work as a clinician, Ladha has observed that children between eight and 13 do not appear to be developing long COVID often.

"I did notice that the ones that have long COVID were generally over the age of 13," she said.

"I can see evidence of what they've shown in this article in my own practice."