Between August 2020 and March 2022 about 118,000 children and young adults were hospitalized for COVID-19. Others were hospitalized for a post-infection complication of COVID-19 known as multisystem inflammatory syndrome in children or MIS-C. For some, their pandemic experience was far more disruptive than the pain of lockdown.

A recent study looked at children and young adults hospitalized with COVID-19 or MIS-C to see how they fared. With in-person school starting back up, the findings support the case for vaccinating children and teens.

“The risks of severe illness and lingering complications are much higher than the risk of complications from vaccines, which are rare.”

Researchers at Boston Children’s Hospital and Children’s Hospital Colorado found that when these previously hospitalized children were examined at a two- to four-month follow-up, 27 percent of those with acute COVID-19 and 30 percent of those with MIS-C still had persistent symptoms, activity impairment or both.

Although these rates are better than those in older adults who were hospitalized, they are still worrisome. “The risks of severe illness and lingering complications are much higher than the risk of complications from vaccines, which are rare,” Adrienne Randolph, lead investigator on the study and a senior associate in critical care medicine at Boston Children’s Hospital, said in a statement.

“Anything we can do, such as vaccines and preventive measures, to decrease the risk of hospitalization from these illnesses is important to do,” Aline Maddux, first author of the study, told TheDoctor.

The study relied on data from the survey responses of caregivers of over 275 children and young adults under age 21 who were hospitalized with COVID-19 or MIS-C between May 2020 and May 2021 when vaccines against SARS-CoV-2, the virus that causes COVID-19, were not yet available. All the participants were part of the Overcoming COVID-19 study, a long-term prospective study done at 25 pediatric hospitals in the U.S.

Fatigue and weakness were the most common lingering symptoms among the group, affecting 11.3 percent of the children and young adults with COVID-19 and 20 percent of those with MIS-C. Shortness of breath affected about nine percent of those with COVID-19 and two-and-a-half percent of those with MIS-C.

Other symptoms affecting those with COVID or MIS-C were cough, headache, muscle and body aches and fever.

Impaired activity was more common after MIS-C than COVID-19, affecting about 21 percent of those with MIS-C and 14 percent of those with COVID-19.

Children whose COVID-19 infections involved more organ systems were at greater risk for prolonged symptoms and a loss of activity. Underlying respiratory conditions, such as asthma, were a risk factor in those with MIS-C, as was obesity. MIS-C patients with preexisting respiratory symptoms were treated with steroids, sometimes for a prolonged period, Maddux said. That exposure could cause persistent fatigue and weakness, particularly in those with underlying asthma.

Studies to measure the cognitive status of those who are hospitalized are underway. The goal is to better understand what, if any, cognitive impairments patients who have prolonged symptoms and reduced activity over the long-term might have.

To fully understand why some kids and young adults recover from the infection and why others have prolonged symptoms will require further research, Maddux, a pediatric critical care specialist at Children’s Hospital Colorado, explained. “In particular, some obesity risk factors could be the focus of future studies,” to determine if something different about patients who have obesity in their physiologic makeup puts them at risk for having prolonged symptoms.

The study is published in Pediatrics.