Amid the escalating volume of calls to reopen Minnesota and the nation, it's important to sound a note of caution. We still have much to learn about the new strain of coronavirus that causes COVID-19, and it's important not to lose sight of that even as normal life resumes.

A mysterious new condition in children is a worrisome warning to not become overconfident in the battle against this virus. As the pandemic unfolded, one silver lining has been that the virus had gone easier on children. Those 19 and under can be infected, but deaths in this age group are rare, and none have occurred in Minnesota.

Recent developments, however, suggest that children infected with the virus can later develop a serious illness called "multisystem inflammatory syndrome," often abbreviated as MIS-C. The condition, thankfully, remains rare. Reported cases in Europe and the U.S. are in the hundreds, not thousands, said Dr. Anu Kalaskar, an infectious disease specialist with Children's Minnesota hospitals and clinics. Five cases, none of them fatal, had been reported in Minnesota as of Friday.

The condition's emergence here and elsewhere illustrates how much is still unknown about the virus's impact on health. In mid-May, the U.S. Centers for Disease Control and Prevention (CDC) sent out a health alert advising medical providers about MIS-C and providing a case definition to help them identify it. MIS-C's name describes what happens to those who develop it. What Kalaskar calls a "hyperinflammatory process" can occur after infection with COVID-19 even if the child didn't feel sick initially. The condition is similar to the rare pediatric condition called Kawasaki disease.

Symptoms include fever, abdominal pain, vomiting, diarrhea, neck pain, rash, bloodshot eyes and fatigue, according to the CDC. The condition can take a serious turn when the inflammation affects multiple organ systems, Kalaskar said. Supportive care is available, but there isn't a specific treatment.

The CDC urges parents to watch kids carefully as COVID-19 continues and to seek medical advice "immediately" if they have concerns about their child's health. Kalaskar also emphasizes that MIS-C is rare and serious cases of it even more so.

Gov. Tim Walz's decision last week to further ease social distancing will allow Minnesotans to go back to health clubs, dine inside restaurants and enjoy bigger gatherings with friends and family. MIS-C's emergence should prompt continued coronavirus vigilance even as we return to public life.