What Parents Should Know About the Current Investigation of Hepatitis of Unknown Cause in Children

While rare, children can still have severe hepatitis (inflammation of the liver), and we don’t always know the cause. It is not unusual for the cause of hepatitis in children to remain unknown; some estimates suggest 30-50% of hepatitis cases in children are from unknown causes.

Investigators are still trying to understand the cause

At this time, the cause of the hepatitis in the children under investigation is still unknown. Some of the more common causes of hepatitis, such as Hepatitis A or B viruses, have been ruled out for this investigation. Some children tested positive for adenovirus, a common virus that typically causes cold- or flu-like illness, or stomach or intestine problems. While some children with hepatitis tested positive for adenovirus, we do not know if this is the cause of the hepatitis cases.

CDC is examining other infections, such as COVID-19, and other factors including exposures to toxins, to see if they might be involved. We are asking parents lots of questions about exposures to products and things in the environment, but so far these children don’t have any in common.

Most of the children under investigation are around 2 years old; most were not eligible to receive a COVID-19 vaccine. COVID-19 vaccination is not the cause of these illnesses.

This is a rare but serious event

Hearing about hepatitis in children can be concerning, but severe hepatitis in children remains rare. Cases of hepatitis in children over the past few years appear stable and are small numbers overall. CDC is taking the investigation seriously and is regularly updating the Investigation Updates page.

Keep your children healthy

Contact your child’s healthcare provider if your child has symptoms listed below, especially jaundice (yellowing of the skin or eyes).

Watch for symptoms of liver inflammation:

  • jaundice (yellowing of the skin)
  • fever
  • fatigue
  • loss of appetite
  • nausea
  • vomiting
  • abdominal pain
  • dark urine
  • light-colored stools (poop)
  • joint pain

Keep your child up to date on all their vaccinations.

Help your family prevent disease:

  • wash hands often,
  • avoid people who are sick,
  • cover coughs and sneezes, and
  • avoid touching the eyes, nose, or mouth.
Page last reviewed: May 6, 2022