A cluster of serious cases of childhood hepatitis in Alabama prompted the Centers for Disease Control and Prevention to issue a nationwide health alert Wednesday, urging doctors and health officials to monitor and report similar cases.
Officials are investigating the possibility that an adenovirus, one of a group of common viruses that can cause cold symptoms, as well as gastroenteritis, pink eye and other conditions, may be responsible.
Hepatitis is inflammation of the liver that has a wide variety of causes, including viruses, exposure to chemicals, some medications, and other medical conditions.
The Alabama Department of Health has recorded nine unexplained cases of hepatitis in otherwise healthy children under 10 that occurred between October and February. None of the children died, but several developed liver failure and two had to undergo liver transplants.
All nine children tested positive for adenovirus infections. Several have been found to have what is known as adenovirus type 41, which typically causes diarrhea, vomiting and respiratory symptoms.
Adenoviruses are known to cause hepatitis, but most commonly in immunocompromised children.
“It’s not typical for healthy children to cause complete liver failure,” said Dr. Aaron Milstone, a pediatric infectious disease specialist at the Johns Hopkins Children’s Center.
The CDC has ruled out some common causes of liver inflammation, including the hepatitis A, B and C viruses, in the Alabama cases, the agency said in a statement on Thursday.
“Right now, we think adenovirus may be the cause of these reported cases, but researchers are still learning more — including ruling out other possible causes and identifying other possible contributing factors,” the agency said.
Similar cases have recently been reported in Britain.
Many questions remain about the cases of hepatitis, which remain rare, experts emphasized.
“It’s important not to panic,” said Dr. Richard Malley, an infectious disease physician at Boston Children’s Hospital. “But I think, for all the reasons you can imagine, it’s important for the CDC to ask clinicians across the country to be vigilant.”
Bertha Hidalgo, an epidemiologist at the University of Alabama at the Birmingham School of Public Health, agreed: “A cluster of cases, especially among this age group, is definitely something to watch closely.”
While it is possible for an adenovirus to be a cause, the link remains unproven. Doctors noted that adenovirus infections are common in children and that the children may have been infected with the virus occasionally.
So far, there is no clear link to the coronavirus causing Covid-19, experts say. Although several British children tested positive for the coronavirus, none of the children in Alabama had Covid, according to the CDC.
dr. Milstone said he thought a connection to the coronavirus was “unlikely” but could not be ruled out completely. “You have to put a question mark there,” he said.
The agency asks health care providers to test children with unexplained hepatitis for adenovirus infections and report these cases to health officials.
Signs of severe hepatitis include prolonged fever, severe abdominal pain and jaundice, yellowing of the skin and eyes; health care providers who observe these symptoms should contact the child’s pediatrician immediately, said Dr. malley. Even severe cases of hepatitis are treatable, he added.
And if the cases are viral, the same strategies many families have used to reduce the risk of Covid — including hand washing and coughing and sneezing — will be helpful prevention strategies.
“All those things they’ve learned about how to protect their kids from Covid will help protect their kids from other viruses,” said Dr. Milstone.
