An infection with an Adenovirus (or an Mastadenovirus) commonly results in a respiratory tract infection. Typical symptoms range from just of a common cold, such as nasal congestion, coryza, and cough, to difficulty breathing as in pneumonia. Other general symptoms can include fever, fatigue, muscle aches, headache, abdominal pain, and swollen neck glands. Very young children may just have an earache. However, some people may have no symptoms at all.
Human Adenovirus type 7 (HAdV-7) is known to cause a more severe disease than other types[2]. It is a strain that's known to cause respiratory symptoms and spread among people living in close quarters, including military recruits. HAdV-7 has also been tied to cases of severe pneumonia and death in infants in South America.
Recently, researchers of the Centers for Disease Control and Prevention (CDC) described cases of eight US children who died of acute hepatitis of unknown cause - half of whom tested positive for adenovirus - between October 2021 and June 2023.
A total of 392 pediatric hepatitis cases of unknown origin were reported during the period. Of the eight who died, two had weakened immune systems, and one of the four who tested positive for adenovirus had no underlying medical conditions. Two children required a liver transplant.
Before these cases, adenovirus had been associated with hepatitis only in people with impaired immune systems. Another 1,010 similar cases were later reported by other countries.
A vaccine against adenovirus strains 4 and 7 is approved by the U.S. Food and Drug Administration, but it is available only for members of the US military.
[1] Almendares et al: Deaths Associated with Pediatric Hepatitis of Unknown Etiology, United States, October 2021–June 2023 in Emerging Infectious Diseases -2024. See here.
[2] Fu et al: Human adenovirus type 7 infection causes a more severe disease than type 3 in BMC Infectious Diseases - 2019
