Anderson spoke about the disease while accepting amfAR's award of courage.
Of a subset of 156 cases with data on hospital admission, about 14% required intensive care, and 12% needed a liver transplant.
Two-thirds of the children tested positive for adenovirus, which is a common virus that typically causes cold or flu-like illness, health officials said.
There are at least 109 cases of hepatitis among children in the U.S.
In Minnesota, one of the latest to see cases, two children have required liver transplants. One of them still waiting.
A Chicago hospital found a fourth possible case of hepatitis in kids reported in Illinois.