Health officials in Westchester County announced Friday that a child being treated for a mystery illness believed to be linked to the coronavirus has died.

The illness, called Pediatric Multi-System Inflammatory Syndrome Associated with COVID-19, prompted an advisory to healthcare providers to immediately report any related symptoms.

County Health Commissioner Dr. Sherlita Amler said officials are still assessing whether underlying conditions were a factor in the child’s death.

Meanwhile, Governor Andrew Cuomo announced a 5-year-old boy in New York City had died from COVID-related complications, but it was not immediately clear if the child was also being treated for the inflammatory syndrome.

Cuomo says there are now 73 reported cases of severe illness in children.

“The loss of a child is an unfathomable tragedy,” New York City Health Commissioner Dr. Oxiris Barbot said. “With aching hearts, we will continue working with hospitals to ensure that New Yorkers have the information they need to keep their children safe. If a child has symptoms of fever, rash, abdominal pain or vomiting, parents should call their doctor right away.”

The purpose of the health advisory is to inform healthcare providers of the condition, as well as to provide guidance for testing and reporting. Healthcare providers, including hospitals, are required to report to the Department of Health all cases of pediatric multisystem inflammatory syndrome potentially associated with COVID-19 in those under 21 years of age.

“I don’t think it’s caught anyone off guard,” Governor Andrew Cuomo said. “It’s developing right now. We are looking at it in New York. The information is all preliminary. We are talking to some hospitals that have some individual cases that they are questioning. But it looks like, again preliminary, young children who either test COVID positive or test for the COVID antibodies which indicate they had the virus, which have an inflammatory response. It’s not really respiratory, it’s more in the blood vessels themselves, where they have an inflammatory response to the virus itself or to the antibodies.”

The possible link has also been reported in the United Kingdom between pediatric COVID-19 and serious inflammatory disease. The inflammatory syndrome has features which overlap with Kawasaki disease and toxic shock syndrome and may occur days to weeks after acute COVID-19 illness.

It can include persistent fever, abdominal symptoms, rash, and even cardiovascular symptoms requiring intensive care.

Health officials say early recognition by pediatricians and referral to a specialist including to critical care is essential, and molecular and serological testing for COVID-19 in children exhibiting the above symptoms is recommended.

The majority of patients have tested positive for COVID-19, some on molecular testing for SARS-COV-2, others on serological testing.