The omicron variant is more likely than other coronavirus variants to cause upper airway infection (UAI) among children, which puts them at risk of heart attack and other severe complications, even as the overall risk for serious illness for children remains low, according to a study published Friday by JAMA Pediatrics.
The omicron variant generally causes less severe disease than the delta variant among all age groups, but is more likely than delta to cause UAIs like croup among children, researchers affiliated with the University of Colorado School of Medicine, Northwestern University Feinberg School of Medicine and Stony Brook University Department of Biomedical Informatics determined.
UAI can put children at particular risk of cardiac arrest and other serious complications because their small breathing passageways are relatively easily blocked, researchers said.
The percentage of children hospitalized with Covid-19 who were also found to have UAI rose from 1.5% in the pre-omicron period (March 1, 2020 to December 25, 2021) to 4.1% in the omicron period (December 26, 2021 to February 17, 2022), according to the study.
Researchers also found that omicron tended to inflict UAI on younger children—the mean age of a hospitalized child with Covid-19 and UAI fell from about 4 years and five months during the pre-omicron period to about 2 years and one month during the omicron period.
Overall, 21.1% of children hospitalized with both Covid-19 and UAI developed severe disease requiring measures like inserting a tube into the lungs to assist with breathing.
Measuring the relative severity of the omicron variant has posed a challenge for scientists. Though research conducted around the time omicron established its dominance in the U.S. indicated that it was simply a more infectious and less severe version of the delta variant, concerns soon emerged about omicron’s effect on children. A study published February 15 by the Centers for Disease Control and Prevention found that children were about four times as likely to be hospitalized with Covid-19 during the omicron period than during the delta period. Scientists have proposed various explanations: because children are less likely than adults to have Covid-19 immunity from vaccination or previous infection, they may be more vulnerable to omicron in some ways. Andrew Pavia, head of University of Utah Health’s Division of Pediatric Infectious Diseases, also suggested that omicron might infect the upper airways more easily than the lungs, decreasing the risk of severe lung-based illnesses but increasing the risk of upper respiratory illnesses, to which children are especially vulnerable. While the rate of Covid-19-caused UAI among children is not “overwhelmingly high,” further study could help guide treatment for young patients, wrote the authors of the JAMA Pediatrics study.
In the U.S., Covid-19 vaccines have been authorized for people age 5 and up. Despite this, 30% of people in the U.S. age 5 and up have yet to be fully vaccinated, according to the CDC. Younger people are generally less likely to be vaccinated than older people.
12.87 million. That’s the cumulative number of child Covid-19 cases reported in the U.S. as of April 7, according to the American Academy of Pediatrics.
While the omicron variant has increased infection rates among children, the risk of severe illness among children remains extremely low. Data from the CDC and the JAMA Pediatrics study indicate that a child’s risk of being hospitalized with Covid-19 is roughly 1 in 14,085, while a child’s risk of being hospitalized with Covid-19 and developing a UAI and severe symptoms is roughly 1 in 10 million. The risk of severe illness among children hospitalized with Covid-19 has also fallen to roughly 3.4% during the omicron period, down from 38.8% during the pre-omicron period, according to the JAMA Pediatrics study. While child deaths in the JAMA Pediatrics study were too rare to be precisely quantified, an American Academy of Pediatrics survey of data from 46 states found that children accounted for between 0% and .27% of cumulative Covid-19 deaths in each state, with three states reporting no child Covid-19 deaths.