For many adults who are vaccinated against COVID-19, life has pretty much returned to normal, including planning vacations, seeing friends and family and eating in restaurants.

Unless they have kids under 12. While Pfizer’s vaccine has been approved by the Food and Drug Administration under emergency use authorization for kids as young as 12, there’s currently no vaccine available for children who are younger than that.

To some, that might not seem like a huge deal: Many children who become infected with COVID-19 are asymptomatic or have few symptoms, and young children are less likely than older adults to develop severe COVID-19 symptoms.

But kids can develop what have come to be known as long-haul COVID-19 symptoms.

Even as COVID-19 infections trend downward, new, more infectious and potentially severe variants of the coronavirus have emerged. As they weigh kids’ summer and fall plans, what do parents need to know about potential long-term COVID-19 effects in children?

Long COVID

As in adults, long COVID in children describes symptoms of illness that linger long after infection. That can include muscle and joint pain, fatigue, and loss of taste and smell, among many other symptoms.

“They have persistent fatigue. People describe brain fog, headache, body aches,” said Dr. Beth Thielen, an assistant professor in the Department of Pediatrics at the University of Minnesota’s Medical School.

As of April, the U.K.’s Office for National Statistics estimated 13.7 percent of people who tested positive for COVID-19 were experiencing symptoms at least 12 weeks later. Recent research found between one-quarter and one-third of patients who visited clinics with COVID-19 but were not hospitalized with the virus had long-haul symptoms. Often they were patients who had mild cases of COVID-19 in the first place. While underlying health factors like diabetes and obesity were predictors of people’s likelihood to end up in the hospital with COVID-19, underlying health factors are not as predictive of long-haul symptoms.

The causes of long COVID still aren’t well understood. But if long COVID is little understood in adults, it’s even less so in kids.

“There’s a few papers out that describe an incidence of long-term complications in children, but I don’t think we have good numbers at this point — we don’t have a good denominator to know how many children have been infected with COVID and what fraction of them develop persistent symptoms,” Thielen said.

A U.K. estimate suggests 12.5 percent and 14.5 percent of kids ages 2 to 16 still had COVID-19 symptoms five weeks after infection, with lingering symptoms seemingly more common among older kids than younger kids.

The other concern with kids and COVID-19 is multisystem inflammatory syndrome in children, or MIS-C, which causes potentially life-threatening inflammation in multiple systems of the body, which can include the heart, lungs and kidneys, among others.

“Often, the initial infection is mild, or maybe not even clinically apparent, and then they come into the hospital, sometimes severely ill with inflammation of multiple organ systems, most severely affected in the heart,” Thielen said.

As of late-June, Minnesota had documented 95 cases of MIS-C, with no deaths. Roughly two-thirds of cases were in kids ages 6 to 19, while one-third were in kids 5 and under, and data show racial disparities, with Black and Hispanic kids disproportionately likely to have been diagnosed with MIS-C than white kids.

Hospitalization for kids with complications from COVID-19, including long COVID and MIS-C is relatively rare, Thielen said, but not unheard of. M Health Fairview has a dedicated clinic for caring for kids with COVID-19 complications, which sees children from Minnesota and surrounding states.

“As a population it’s still relatively rare,” Thielen said. But she and others are concerned that could change.

“We’re seeing some signs, with these variants circulating, that we’re seeing more severe disease in young people, and the age of people getting hospitalized is dropping,” she said.

Taking precautions

Experts say a vaccine for kids under 12 may not be available for months. For parents who have to make decisions about enrolling their unvaccinated kids in activities soon, Thielen recommends assessing risk, taking into account things like kids’ social emotional well-being, and any underlying risks if a kid or family member is immunocompromised.

Families who want to get back to doing activities and be mindful of COVID-19 can track transmission rates to better understand local risk. They can also find activities that take place outdoors, keep kids in smaller pods and require unvaccinated children to be masked.

“I don’t think that this is a situation where there’s uncertainty and I think it’s very hard to make a one size fits all kind of recommendation,” she said. “The risk still is relatively small. I mean, it’s not zero, you have to accept that, but we accept risks driving cars and flying in planes and going on roller coasters — there’s all these activities where we are weighing risks and benefits and this is no different.”