CDC is investigating a possible association between pediatric hepatitis and adenovirus infection. Visit CDC’s NCIRD site for information about the investigation.

Children with Acute Hepatitis of Unknown Cause

Health advisory

CDC released a Health Alert Notice for clinicians and a media statement for parents and caregivers.

Clinicians’ guidelines

Get clinical guidance for adenovirus PCR and possible additional testing.

Testing guidelines

Instructions for testing, typing, and submission

Adenoviruses usually cause respiratory illnesses or conjunctivitis, and outbreaks can occur throughout the year. There is no specific time of year when adenovirus infections and outbreaks are more common.

Adenoviruses is not a nationally notifiable disease in the United States, meaning clinicians are not required to test for or report cases to health departments or CDC. Therefore, many outbreaks of adenovirus likely go either undetected or unreported.

Adenovirus types that can cause outbreaks

Reported sporadic cases and outbreaks of adenovirus have included:

Acute respiratory illness

Adenovirus types 3, 4 and 7 are most commonly associated with acute respiratory illness.

Adenovirus type 14 which has been associated with outbreaks of acute respiratory illness among U.S. military recruits and the general public.

Severe outcomes

Adenovirus types 4 and 7 has been associated with more severe outcomes than other adenovirus types, particularly in people with weakened immune systems. In the last 10 years, instances of severe illness and death from adenovirus type 7 infection have been reported in the United States.

Epidemic keratoconjunctivitis

Adenovirus types 8, 19, 37, 53, and 54, which can cause epidemic keratoconjunctivitis.


Enteric adenovirus types 40 and 41, which cause gastroenteritis, usually in children.

Spread in bodies of water

Some adenoviruses (e.g., 4 and 7) that spread in bodies of water, such as small lakes or swimming pools without adequate chlorine and can cause outbreaks of febrile disease with conjunctivitis.

General public should

Health professionals should

  • Consider adenoviruses as possible causes of upper respiratory illness, and lower respiratory illness such as pneumonia.
  • Report unusual clusters of illness (e.g., respiratory, conjunctivitis) potentially caused by adenoviruses to the State or Local health department.
  • If potential outbreaks in healthcare settings are identified, take appropriate infection control measures specific to adenovirus to help prevent or control outbreaks. This can include active surveillance, isolating ill patients when possible, restricting visitors and new admissions, monitoring staff for illness and sending them home when sick, environmental cleaning, using personal protective equipment, and frequent handwashing or sanitizing.

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