August 4, 2022 – CDC researchers report that children and adolescents with long-term COVID are about twice as likely to have severe outcomes, compared to others without COVID.

Heart inflammation; a blood clot in the lungs; or a blood clot in the lower leg, thigh or pelvis were the most common poor outcomes in a new study. Although the risk was higher for these and some other serious events, the overall numbers were low.

“Many of these conditions were rare or uncommon among children in this analysis, but even a small increase in these conditions is notable,” a new CDC statement said.

The investigators said their findings underscore the importance of COVID-19 vaccination for Americans under 18.

The study was published online Thursday in the CDC’s Morbidity and Mortality Weekly Report (MMWR).

Less is known about the long COVID in children

Lyudmyla Kompaniyets, PhD, and colleagues noted that most research on long COVID to date has been done in adults, so little information is available on the risks for Americans ages 17 and younger.

To find out more, they compared post-COVID symptoms and conditions between 781,419 children and adolescents with confirmed COVID-19 to 2,344,257 without COVID-19. They looked at the medical claims and lab data of these children and teens from March 1, 2020 through January 31, 2022, to see who got one of 15 specific long COVID-related results.

Long COVID was defined as a condition where symptoms last or begin at least 4 weeks after a diagnosis of COVID.

Compared to children with no history of COVID-19 diagnosis, the long COVID-19 group was:

  • 101% more likely to have an acute pulmonary embolism (blood clot in the lungs)
  • 99% more likely to have myocarditis (inflammation of the heart muscle) or cardiomyopathy (when the heart is weak and has trouble pumping blood)
  • 87% more likely to have a venous thromboembolic event (blood clot in a vein)
  • 32% more likely to have acute, unspecified kidney failure (when the kidneys cannot filter waste from your blood)
  • 23% more likely to have type 1 diabetes

“This report underscores the fact that the risks of infection from COVID itself, both in terms of acute, MIS-C, and long-term effects, are real, concerning, and potentially very serious,” says Stuart Berger, MD, chair of the American Academy of Pediatrics Section of Cardiology and Cardiac Surgery.

MIS-C is a multisystem inflammatory syndrome in children, a condition where many parts of the body become inflamed, which has been linked to COVID-19.

“The message we should take from this is that we should be very careful about all methods of COVID prevention, 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 results are “sobering” and “a reminder of the seriousness of COVID infection,” says Gregory Poland, MD, an infectious disease expert at Mayo Clinic in Rochester, MN.

“When you look particularly at the more serious complications of COVID in this young age group, these are life-changing complications that will have consequences and ramifications throughout their lives,” he says.

“I would take this as a serious wake-up call for parents [at a time when] vaccination rates in young children are so pitifully low,” says Poland.

Still the first days

The study is suggestive but not definitive, says Peter Katona, MD, professor of medicine and infectious disease expert at the UCLA Fielding School of Public Health.

It is still too early to draw conclusions on long COVID, including in children, as many questions remain, he says: Should long COVID be defined as symptoms at 1 month or 3 months after infection ? How would you define brain fog?

Katona and colleagues are studying a long COVID intervention among UCLA students 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 their severity; some people in the non-COVID group might have had the disease but not been diagnosed; and the researchers did not adjust for vaccination status.

Poland notes that the study was carried out during peaks of COVID variants, including Delta and Omicron. In other words, the long COVID effects related to newer variants like BA.5 or BA.2.75 are unknown.