Most of the children who fell ill were toddlers, and nearly all required hospital treatment.
Dr Jay Butler, the CDC’s deputy director for infectious diseases, asked for doctors to be on the lookout for possible cases of liver disease in a conference call on Friday.
“It’s important to note that this is an evolving situation, and we are casting a wide net to broaden our understanding,” he said.
Dr Butler said approximately half of the children diagnosed with hepatitis had also been infected with a type of adenovirus, – a virus that causes the common cold.
The agency is still investigating the exact cause of the illness, he said.
Hepatitis linked to this type of adenovirus has mostly been associated with immunocompromised children, but many of the cases first reported to the CDC did not have immunocompromising conditions, Dr Butler said.
Hepatitis can be caused by toxins, viral infections, autoimmune diseases and drugs. Hepatitis A, hepatitis B and hepatitis C are the most common types in the United States.
The latest outbreak was first detected in Alabama in November, when state health officials began looking into the first of nine cases of severe hepatitis in children in that state. None tested positive for the viruses that commonly cause hepatitis. However, testing was positive for adenovirus.
Dr Butler said none of the Alabama children were vaccinated against Covid-19. That has been ruled out as a possible cause, “and we hope this information helps clarify some of the speculation circulating online.”
“It´s still a very rare occurrence,” Dr Butler said. “A majority of these cases have recovered and recovered fully.”
Symptoms of hepatitis, or inflammation of the liver, include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain and jaundice.
In addition to Alabama, the states reporting suspected cases: California, Colorado, Delaware, Florida, Georgia, Idaho, Illinois, Indiana, Louisiana, Michigan, Minnesota, Missouri, North Carolina, North Dakota, Nebraska, New York, Ohio, Pennsylvania, Tennessee, Texas, Washington, Wisconsin. Puerto Rico also reported at least one case.
The CDC did not reveal how many cases had been found in each state or any information about the victims due to “confidentiality issues”.
Alabama state officials had previously reported nine cases in the state, the largest known outbreak.
The World Health Organisation (WHO) said earlier this week there were almost 300 probable cases of children with severe hepatitis detected in 20 countries worldwide.
In the United Kingdom, where 163 children have contracted the illness, health authorities are investigating a possible link to dog ownership.
The UK Health Security Agency said this week that 64 of 92 cases they were exmaining had reported exposure to dogs. None of the UK cases have been fatal.
Agencies contributed to this report