COVID: How different variants affected Canadian children

A new study of more than 1,400 Canadian children with COVID-19 found that fever and cough were associated with the Omicron and Delta variants, but serious outcomes such as hospitalization and intensive care unit transfers remained even across the variants.

The fact that rates of hospitalizations and intensive care unit transfers remained stable even with the later versions may be a sign that when it comes to children, the virus isn’t getting any softer, the researchers said.

“Unlike adults, children appear to be less affected by emerging variants, and understanding the clinical presentation of COVID-19 in children is necessary to design therapeutic trials in this population,” the researchers wrote.

The question of how severe the different variants are and how they manifest differently in populations is one that researchers have posed for the entire epidemic.

In this new study, published Thursday peer-reviewed journal JAMA Network Openresearchers wanted to investigate whether children had different symptoms depending on which variant of COVID-19 they contracted.

They studied 7,272 children who presented to one of 14 pediatric emergency departments between August 2020 and February 2022 and were tested for COVID-19.

Around 1440, the virus tested positive. Just over half, 55 percent, were boys, and the average age was two.

It is known that different variants tend to affect the body differently, previous studies have indicated that Omicron variants tend to infect the upper respiratory tract more easily than other variants.

But not many studies have observed this effect in children.

Compared to the original strain of COVID-19, both Delta and Omicron had higher rates of fever and cough, the study found.

In terms of which part of the body symptoms were most affected, upper respiratory symptoms were associated with Delta infection, while lower respiratory symptoms were more common with Omicron infection.

Children infected with Omicron are also more likely to have more systemic symptoms beyond purely respiratory symptoms. Children infected with the alpha variant had the fewest individual symptoms of COVID-19.

Despite differences in symptoms caused by the individual variants, there was no clear difference in the proportion of children hospitalized or admitted to the intensive care unit.

However, children infected with Omicron were more likely to have additional visits to the emergency department compared with those infected with Delta.

Patients with Omicron were also more likely to have chest radiographs, intravenous surgery during their hospital stay, and to receive corticosteroid treatment.

“Although several reports have shown that Omicron is responsible for less severe disease than previous versions, particularly among adults, we found that children with Omicron infection received more interventions and were more likely to experience ED repeat visits,” they write. are the researchers. “Our findings are not unique as they are consistent with other pediatric studies reporting higher rates of pediatric hospitalizations during the Omicron period.”

All 14 Canadian pediatric emergency departments from which the data were obtained are part of the Canadian Pediatric Emergency Research Network.

All patients enrolled in the study were then contacted by telephone two days after the emergency department visit to collect demographic, clinical, or epidemiologic data, as well as data on any comorbidities.

The researchers also surveyed 1,224 participants two weeks later to see how things had progressed. A total of 998 participants provided information on whether or not the child had been vaccinated, with only eight percent receiving at least one dose.

In terms of the most common individual symptoms, 75 percent of the group had a fever, 56 percent had a cough, and 53 percent had a runny nose.

The alpha variant was infected with the fewest symptoms considered to be “core” COVID-19 symptoms: fever, cough, and loss of taste/smell. Of all the participants, 89 percent of the children had at least one of these three symptoms, and they were most common among the Omicron patients.

The alpha variant also had the lowest percentage of patients reporting drowsiness, pink eyes, changes in the mouth, runny nose or sore throat as symptoms.

Delta infection was associated with the highest percentage of patients with pink eye and cough as symptoms, with 61 percent of Delta patients having a cough.

The researchers noted that the proportion of children with severe illness was lower than measured in the previous study, noting that this may be because some of the emergency department visits included in this study were for a COVID-19 test. and were not stimulated. with a serious illness.

The study is also limited by the fact that only a third of the group underwent variant testing to ascertain which variant the patients had. All other variant names were determined by which variant was dominant in that region at the time the patient was infected with the virus, which means that there may be errors in the data. Most Alpha and Delta patients have their variants confirmed by testing.