At first, it was believed children were not susceptible to the symptoms of coronavirus, and acted only as carriers.
But disturbing new evidence shows that is unlikely to be true.
In his daily press briefing New York's governor Andrew Cuomo today said almost 100 children statewide who had tested positive for Covid-19 were reportedly showing "toxic shock" symptoms similar to those caused by the so-called Kawasaki disease – a rare inflammatory condition in children.
Tragically, a 5-year-old boy died in New York City this week from the mystery condition linked to the coronavirus, according to Cuomo.
The boy, who died yesterday NZ time, was one of 73 children in the Empire State who had developed symptoms similar to the disease after contracting Covid-19, Cuomo said.
"So this is every parent's nightmare, right? That your child may actually be affected by this virus.
"But it's something we have to consider seriously now."
The Department of Health is investigating the matter.
"This would be really painful news and would open up an entire different chapter because I can't tell you how many people I spoke to who took peace and solace in the fact that children were not getting infected," Cuomo said.
Like thousands of people around the world, many New Yorkers previously believed children were largely unaffected by the coronavirus after initial health experts indicated as such.
Dozens of children elsewhere in the US have been hospitalised with the inflammatory condition that might be linked to the coronavirus and was seen in Europe.
Treatment for Kawasaki disease involves intravenous immunoglobulin and aspirin. Although symptoms are often severe, most sufferers recover without serious issues.
While no link has been formally established to the new coronavirus, scientists believe it could be connected.
In an article published this week in the medical journal The Lancet, British doctors describing eight cases observed in London said it could be "a new phenomenon" affecting previously asymptomatic children with the coronavirus "manifesting as a hyperinflammatory syndrome".
While many children have become infected with the coronavirus, very few have died or contracted serious symptoms, something that had given solace to parents amid the deadly pandemic.
Cuomo told reporters any confirmed link between Covid-19 and Kawasaki disease would be a worrying development.
"This would be really painful news and would open an entirely different chapter," he said. Symptoms include prolonged fever, severe abdominal pain and trouble breathing.
The statewide death toll from the virus is now more than 20,000 and doesn't include more than 5300 deaths in New York City that were attributed to the virus on death certificates but not confirmed by a lab test. Though hospitalisation continued to decrease with an average of around 600 new admissions each day.
Earlier this week, Mayor Bill de Blasio said a rising number of cases in New York City was causing concern.
The revelation comes after Cuomo today extended New York's moratorium on outbreak-related housing evictions for two more months.
The governor in March had issued a moratorium on residential and commercial evictions that lasted through June, but he said he wanted to reduce the anxiety of families struggling through the economic shutdown. It is now extended until August 20.
"I hope it gives families a deep breath," Cuomo said at his daily briefing. The executive order will also ban late fees for missed payments and allow renters to apply their security deposit to a payment, though they'd have to pay it back over time.
New York City will test 140,000 people for coronavirus antibodies between next week and early June, Mayor Bill de Blasio announced yesterday.
The antibody tests, which indicate whether a person has been infected with the virus at some point, would be offered for free by appointment at five locations, the mayor said. The results would be available in one to two days and would also be used for research, he said.
Researchers say it is unclear whether coronavirus antibodies provide immunity from further exposure to the germ. The human body produces antibodies days or weeks after fighting an infection. Most tests use a finger prick of blood on a strip.
"We are not promising people a rose garden here," de Blasio said.
"We're not saying the antibody test is the last word. It's not. But it tells you something."
The city will use tests made by BioReference Laboratories for the free programme. The state has already performed antibody tests on about 27,000 workers at health care centres in the New York City area.
At a separate briefing yesterday, Cuomo said those workers tested positive for antibodies at a lower rate than the general population, a finding he said showed the effectiveness of protective masks and gloves for frontline workers.
"That is amazingly good news," he said.
"We were afraid of what was going to happen."
The survey found 12 per cent of health care workers in New York City tested positive for antibodies, compared with 20 per cent for the city's general population. Positive rates for health care workers in Westchester County, just north of the city, were about half of those for the general population, though worker rates were roughly the same on Long Island.