Cases of severe acute hepatitis in children are being reported in an increasing number of countries and the cause is unknown, the World Health Organization said on Saturday.
A total of 169 cases of acute severe hepatitis in children had been
reported in eleven countries by 21 April. The children affected range in age from
one month to 16 years old.
So far, one death and 17 liver transplants have been
reported as a result of the hepatitis outbreak, the World Health Organization
revealed on Saturday.
Most cases have been reported in the United Kingdom (114),
where the condition was first identified.
The syndrome presents in the form of acute hepatitis with
elevated liver enzymes. In many cases gastrointestinal symptoms such as abdominal
pain, diarrhoea and vomiting have preceded the development of severe hepatitis.
AST and/or ALT levels above 500 IU/ml have been accompanied by jaundice. Fever
is absent in most cases.
Viral hepatitis has not been detected in any of the cases
and all the children presenting with the syndrome were described as previously
healthy.
Very few of the affected children had been vaccinated
against SARS-CoV-2, ruling out an adverse vaccine reaction as a cause of the
syndrome.
Adenovirus has been detected in at least 74 cases, 20 cases
have been diagnosed with SARS-CoV-2 and in 19 cases, SARS-CoV-2 was detected
alongside adenovirus. Further information on testing for each infection is
needed.
Although an adenovirus infection has been proposed as a
cause of the syndrome, no adenovirus type has been linked to an acute hepatitis
syndrome. Adenovirus F type 41, detected in 18 cases, may cause gastrointestinal
symptoms, fever and respiratory symptoms.
The World Health Organization says that “other infectious
and non-infectious explanations need to be excluded to fully assess and manage
the risk.”
Several working hypotheses are being investigated, including
the possibility that a lack of prior adenovirus exposure due to the COVID-19
lockdowns may have left children more susceptible to the effects of resurgent
adenovirus infections. The United Kingdom has observed an increase in adenovirus
infections in the community in recent months.
Another possibility is that prior SARS-CoV-2 infection or
another viral infection could result in a severe reaction to infection by
another virus. A novel pathogen cannot be ruled out.
Alternatively, the syndrome may have a non-infectious cause,
either a drug, toxin or environmental exposure.
Investigations to date have been hampered by a lack of consistent
testing. In England, 40% of cases have not been tested for adenoviruses and the
majority have not been tested for enteroviruses or other common viral causes of
childhood illnesses, according to a technical briefing issued by the UK Health Security Agency on 25 April.