For the study, researchers analyzed data from 45 U.S. children’s hospitals between April 2020 to September 2020 of pediatric patients who were diagnosed with COVID-19. The study included nearly 20,000 children. 

Of those who were hospitalized, 3,222 had moderate COVID-19, 431 had severe COVID-19, and 380 had a very severe form of the disease. Of the children admitted to the hospital with COVID, 21% developed severe disease and required ICU care.

The researchers discovered that the following conditions increased the risk of hospitalization for children:

ObesityType 2 diabetesAsthmaHeart diseasePulmonary diseaseNeurologic disease

Among children who were hospitalized, researchers found that children who experienced more severe cases were typically:

Older than fourBlack or non-WhiteDiagnosed with obesity or type 2 diabetesHad cardiovascular, neuromuscular, or pulmonary conditions

“This is one of the largest multi-center studies of children with COVID-19 in the United States,” lead study author James Antoon, MD, PhD, assistant professor of pediatrics at Monroe Carell Jr. Children’s Hospital at Vanderbilt University, said in a press release. “And given the recent, concerning increases in COVID cases nationwide and the fact that the vast majority of children remain unvaccinated and susceptible, these findings should be taken into account when considering preventive strategies in schools and planning vaccinations when available for children less than 12 years of age.”

The September study was published in the Journal of Hospital Medicine.

Children and COVID-19 Cases

COVID-19 cases in children declined in early summer, but have quickly increased over the past four weeks.

In fact, they’ve hit record-high numbers. As of September 16, more than 5.5 million children have tested positive for COVID-19 since the pandemic began.

Nearly 226,000 new cases in children were diagnosed for the week ending September 16, and children make up 25.7% of the reported weekly COVID-19 cases. Worth noting: Children under 18 make up 22.2% of the U.S. population.

Children have largely been spared from serious consequences of COVID-19, but some kids do develop severe cases of infection. Research has shown that hospitalization rates in children aged zero to four have increased 10-fold since the rise of the Delta variant and hospitalization rates among unvaccinated teens is 10 times higher than those who are fully vaccinated.

These Findings Mirror What We Know About Adults

“[The latest study findings] aren’t surprising and mirror what we know about adults who contract COVID-19,” Richard Watkins, MD, an infectious disease physician and professor of internal medicine at the Northeast Ohio Medical University, tells Verywell.

Lawrence Kleinman, MD, MPH, professor and vice-chair of pediatrics at Rutgers Robert Wood Johnson Medical School, tells Verywell that the findings mirror research he’s conducted that also found children who have obesity or an underlying health condition make up the majority of more severe COVID-19 cases.

Still, he says, “anybody can get sick with COVID.”

As for why children may be at higher risk of hospitalization over the age of four, Watkins suggests it could be because their immune systems “start to resemble those of older children and adults” at that point.

Overall, infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security, tells Verywell that the findings underscore the importance of protecting children from COVID-19.

“While children are generally spared the severe consequences of disease, there are some that have high-risk conditions for which COVID-19 is something to be concerned about,” he says.

Kleinman says doctors are also concerned about the possibility of long COVID symptoms in kids. “We don’t yet understand long COVID in kids, and the things that can happen after the acute illness,” he says.

Watkins urges parents to continue to be diligent about protecting their children from COVID-19. “Have them wear masks whenever outside the home, not just at school,” he says. “It is your job as a parent to do everything you can to keep your children safe.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.