Dr. Scott Gottlieb told CNBC on Thursday there are questions and concerns about how children might be contributing to the spread of the coronavirus.
"It might be that thousands of kids are actually getting coronavirus, tens of thousands of kids, and we just aren't seeing it because the kids are getting a very mild illness or they're getting no illness at all," Gottlieb said on "Squawk Box." "But they're still vectors, they're still passing on the virus."
Gottlieb said there are so far "mixed studies" on the rate of infection for children. He said some suggest kids are not getting infected at high rates, while others suggest they are getting infected with "sub-clinical illness" and largely remaining asymptomatic.
Older adults and people who have underlying medical conditions have the highest risk of becoming severely ill from Covid-19. But the way in which the virus impacts kids has taken on new light in recent days after health officials in New York State warned of an inflammatory disease among at least 64 children that is possibly associated with the virus.
Gottlieb, a former commissioner of the Food and Drug Administration, said it appears to be a potential "autoimmune-type condition" that develops after Covid-19 subsides. He said it is a concerning development, but stressed it is difficult to tell how common the condition is without understanding how widespread the coronavirus is among children.
"What we don't know is the denominator. We know the numerator, that a couple of dozen reports now of this syndrome," said Gottlieb, a CNBC contributor who sits on the boards of Pfizer and biotech company Illumina.
Gottlieb noted the number of children who are reporting with active infection of the coronavirus is "very low." According to the most recent data available from the Centers for Disease Control and Prevention, there are about 21,000 confirmed cases of Covid-19 among people who are under 18 years old.
The CDC reports nearly 917,000 confirmed cases overall in the U.S., while data Thursday morning in a widely followed Covid-19 tracker from Johns Hopkins University puts that number at over 1.2 million, which represents about a third of all the cases in the world.
Gottlieb said the role of children in spreading seasonal influenza is well understood and that is why schools were closed in response to the Covid-19 outbreak. He said there is ample data showing that the scope of a flu epidemic is reduced "dramatically" when schools are shut down.
With the flu, children become vectors and spread it throughout the community, said Gottlieb. "We assumed the same was true of coronavirus. We don't have data yet on that."