Three deaths in New York are now linked to the illness known as pediatric multisystem inflammatory syndrome.
More than half of the cases involved children ages 5 to 14. Of those who died, their ages were 5, 7 and 18.
"This is a truly disturbing situation, and I know parents around the state and the country are very concerned about this. They should be," Cuomo said. "If we have this issue in New York, it's probably in other states and hasn't been diagnosed yet in other states because again these children don't present the usual COVID symptoms. They're not respiratory symptoms. and I think thats one of the reasons why people haven't found it yet."
Related: What parents need to know about the mystery syndrome
A total of 52 children in New York City have been diagnosed with an inflammatory syndrome possibly linked to COVID-19 and another 10 cases are pending, Mayor Bill de Blasio said Tuesday.
Of those 62 confirmed or possible cases, 25 have tested positive for the coronavirus and another 22 had antibodies for the virus, de Blasio said.
"It's sobering, it's bluntly frightening," de Blasio said, "and I want to say to parents out there, if you're hearing this information about pediatric multi-system inflammatory syndrome and it sounds scary, it does sound scary."
The mayor urged parents to call their pediatricians promptly if their children show symptoms including persistent fever, rash, abdominal pain and vomiting
Health officials say they are still learning how the disease manifests.
Children elsewhere in the U.S. and in Europe also have been hospitalized with the condition.
New Jersey is reporting eight possible cases, but no deaths, while Yale New Haven Hospital in Connecticut has reported three cases.
Dr. Juan Salazar, the physician-in-chief at Connecticut Children's Medical Center, said two patients there are believed to have the rare conditionn, which he said often appears to present itself two to four weeks after a child has recovered from COVID-19, often without ever being diagnosed with the infection.
Cuomo announced last week that New York is developing national criteria for identifying and responding to the syndrome at the request of the federal Centers for Disease Control and Prevention.
In testimony Tuesday before a Senate committee on the administration's coronavirus response, Dr. Anthony Fauci said children in general do better than adults and the elderly, but he warned there is still much to learn about the virus.
"For example right now, children presenting with COVID-19 who actually have a very strange inflammatory syndrome very similar to Kawasaki syndrome," Fauci said. "I think we better be very careful that we are not cavalier in thinking that children are completely immune to the deleterious effects."
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