More than a dozen children between the ages of 2 and 15 have been diagnosed and hospitalized with an inflammatory syndrome that doctors don't have a good understanding of yet, but which they speculate may have some connection to the novel coronavirus, according to the New York Times.

The mystery disease causes the children to show symptoms of toxic shock or symptoms associated with Kawasaki disease, which is marked by inflammation of the blood vessels, according to the New York City health department.

None of the 15 New York City children who have been hospitalized have died. Despite the extremely small number of children known to be sick with this particular illness, city health authorities put out a bulletin about it Monday.

"The full spectrum of disease is not yet known," the bulletin read. "Of the 15 patients, most either tested positive for the coronavirus or were found, through antibody testing, to likely have been previously infected."

The children exhibited symptoms like rash, vomiting, diarrhea, and respiratory issues. Most of them also "required blood pressure support," the Times reported.

Still, since not all of the 15 sick kids tested positive for COVID-19, it is possible that this sickness is not related to the coronavirus at all. After all, serology studies continue to show that asymptomatic COVID-19 cases are far more common than official statistics reflect.

"Even though the relationship of this syndrome to COVID-19 is not yet defined, and not all of these cases have tested positive for COVID-19 by either DNA test or serology, the clinical nature of this virus is such that we are asking all providers to contact us immediately if they see patients who meet the criteria we've outlined," New York City Health Commissioner Oxiris Barbot said.

In 2009, according to the Centers for Disease Control and Prevention, Kawasaki disease resulted in 5,447 hospitalizations for children under 18 years of age, with 4,040 of them being children younger than 5 years old.