The US Centers for Disease Control and Prevention has warned doctors about a rare inflammatory and sometimes deadly condition that has been found in children and connected to the coronavirus.
The CDC on Thursday issued a health advisory about what it named a "multisystem inflammatory syndrome in children" (MIS-C) that is "associated with" the COVID-19 disease.
It urged medical workers to report anyone who has the symptoms to health departments so more can be learned about it, noting that there is currently "limited information."
It defined the illness as involving someone aged 20 or younger that has been infected by or exposed to the coronavirus, and has had a fever of at least 100.4 degrees Fahrenheit (38 degrees Celsius) for at least 24 hours.
The patient also needs to have laboratory-proved inflammation and "evidence of clinically severe illness requiring hospitalization, with multisystem organ involvement" without any other plausible diagnosis for these problems.
The illness, which has already killed some children, are similar to Kawasaki disease, a disease that inflames the walls of the arteries and typically affects just one in 10,000 children.
Doctors began studying MIS-C as cases surged higher than the usual rate of Kawasaki disease, and as coronavirus cases increased globally.
The CDC said that some cases may look like Kawasaki disease, but their cases should still be reported if they have the symptoms for this new condition.
Doctors in some of the areas worst-hit by the coronavirus around the world have reported cases of this mysterious inflammatory syndrome in children.
Doctors in the UK first reported in April that they were seeing a serious condition that meant children needed intensive care, warning that "there is a growing concern that a [COVID-19] related inflammatory syndrome is emerging in children in the UK, or that there may be another, as yet unidentified, infectious pathogen associated with these cases."
At least one child — a 14-year-old boy — has died from the illness in the UK. Three children in New York have also died from the illness, with the state announcing earlier in May that it is testing children for antibodies.
British medical experts are also researching the illness, the UK government said.
Multiple countries, including France and Spain, have since reported cases.
Doctors in Italy announced Thursday that they found evidence connecting the illness to COVID-19 after finding coronavirus antibodies in the majority of infected children.
Doctors there provisionally gave it the name Pediatric Inflammatory Multisystem Syndrome Temporarily Associated with SARS-CoV-2, or PIMS-TS for short.
The CDC also said Thursday that it is not yet clear if this illness can also affect adults.
The illness poses a new risk to children, which appear less likely to be severely infected by the coronavirus itself, but are believed to help its spread.
