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CDC researchers report that children and teenagers with long COVID have about twice the risk of getting serious outcomes, compared to others without COVID.
Heart inflammation; a blood clot in the lung; or a blood clot in the lower leg, thigh, or pelvis were the most common bad outcomes in a new study. Even though the risk was higher for these and some other serious events, the overall numbers were small.
“Many of these conditions were rare or uncommon among children in this analysis, but even a small increase in these conditions is notable,” a CDC new release stated.
The investigators said their findings stress the importance of COVID-19 vaccination in Americans under the age of 18.
The study was published online Thursday in the CDC’s Morbidity and Mortality Weekly Report (MMWR).
Less Is Known About Long COVID in Kids
Lyudmyla Kompaniyets, PhD, and colleagues noted that most research on long COVID to date has been done in adults, so little information is available about the risks to Americans ages 17 and younger.
To learn more, they compared post-COVID symptoms and conditions between 781,419 children and teenagers with confirmed COVID-19 to another 2,344,257 without COVID-19. They looked at medical claims and laboratory data for these children and teenagers from March 1, 2020, through January 31, 2022, to see who got any of 15 specific outcomes linked to long COVID.
Long COVID was defined as a condition where symptoms that last for or begin at least 4 weeks after a COVID diagnosis.
Compared to kids with no history of a COVID-19 diagnosis, the long COVID-19 group was:
101% more likely to have an acute pulmonary embolism (blood clot in the lung)
99% more likely to have myocarditis (heart muscle inflammation) or cardiomyopathy (when the heart is weakened and has a hard time pumping blood)
87% more likely to have a venous thromboembolic event (blood clot in a vein)
32% more likely to have acute and unspecified renal failure (when the kidneys can’t filter waste from your blood)
23% more likely to have type 1 diabetes
“This report points to the fact that the risks of COVID infection itself, both in terms of the acute effects, MIS-C, as well as the long-term effects, are real, are concerning, and are potentially very serious,” says Stuart Berger, MD, chair of the American Academy of Pediatrics Section on Cardiology and Cardiac Surgery.
MIS-C is multisystem inflammatory syndrome in children, a condition where many parts of the body become inflamed, that has been linked to COVID-19.
“The message that we should take away from this is that we should be very keen on all the methods of prevention for COVID, especially the vaccine,” says Berger, who is also chief of cardiology in the Department of Pediatrics at Northwestern University Feinberg School of Medicine in Chicago.
A “Wake-Up Call”
The study findings are “sobering” and are “a reminder of the seriousness of COVID infection,” says Gregory Poland, MD, an infectious disease expert at the Mayo Clinic in Rochester, MN.
“When you look in particular at the more serious complications from COVID in this young age group, those are life-altering complications that will have consequences and ramifications throughout their lives,” he says.
“I would take this as a serious wake-up call to parents [at a time when] the immunization rates in younger children are so pitifully low,” Poland says.
Still Early Days
The study is suggestive but not definitive, says Peter Katona, MD, a professor of medicine and infectious diseases expert at the UCLA Fielding School of Public Health.
It’s still too early to draw conclusions about long COVID, including in children, because many questions remain, he says: Should long COVID be defined as symptoms at 1 month or 3 months after infection? How do you define brain fog?
Katona and colleagues are studying long COVID intervention among students at UCLA to answer some of these questions, including the incidence and effect of early intervention.
The study had “at least seven limitations,” the researchers noted. Among them was the use of medical claims data that noted long COVID outcomes but not how severe they were; some people in the no COVID group might have had the illness but not been diagnosed; and the researchers did not adjust for vaccination status.
Poland notes that the study was done during surges in COVID variants including Delta and Omicron. In other words, any long COVID effects linked to more recent variants like BA.5 or BA.2.75 are unknown.
Morbidity and Mortality Weekly Report: “Post-COVID-19 Symptoms and Conditions Among Children and Adolescents – United States, March 1, 2020-January 31, 2022,” Aug. 5, 2022.
Stuart Berger, MD, chair, American Academy of Pediatrics Section on Cardiology and Cardiac Surgery; chief of cardiology, Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago.
Gregory Poland, MD, infectious disease expert, Mayo Clinic, Rochester, MN.
Peter Katona, MD, professor of medicine and infectious diseases expert, UCLA Fielding School of Public Health.