There have been 73 reported cases of children presenting with a pediatric multi-system inflammatory syndrome likely linked to COVID-19 in New York City, and a five-year-old boy in the city has died of the condition, raising new concerns about the pandemic's full impact on children. 

The multi-system inflammatory syndrome has features that overlap with Kawasaki Disease, a mysterious illness and Toxic Shock Syndrome, including persistent fever, abdominal symptoms, rash and cardiovascular changes, according to an advisory issued by the state's health department on Wednesday.   

Britain's National Health Service first sounded the alarm last month, warning about a small rise in children infected with the coronavirus that have "overlapping features of toxic shock syndrome and atypical Kawasaki disease."  

France has also reported several cases. 

Though frightening, most recover without serious issues.  

New York government's health department asked health providers to immediately report those cases in patients who are under 21 years old, and perform a diagnostic and serological test to detect the presence of novel coronavirus or corresponding antibodies in the patients.  

Health experts in New York are still trying to figure out whether the syndrome is linked to COVID-19, as not all 73 children tested positive for coronavirus or its antibodies.  

New cases are now showing up in New Jersey as well, with doctors there telling NBC New York that they're are seeing a significant jump in cases with some similarities to the sickness.  

New York City issued its own health alert earlier this week after identifying more than a dozen children in city hospitals who have the rare illness. At least one expert believes there are sure to be more kids affected.  

(With input from agencies)