Acute hepatitis outbreak in children – what we know so far
More than 165 cases of acute, severe hepatitis have been diagnosed in children aged 1 month to 16 years old in 12 countries, suggesting a worldwide outbreak. Of those children affected, 10% required liver transplants, their hepatitis was so severe. Hepatitis is best defined as inflammation of the liver and can have different causes, one of which is viral.
What is the likely cause?
So far, the theory that adenovirus is the cause of this outbreak of hepatitis in children is increasingly widely supported.
Adenoviruses are a group of common viruses that affect children more than adults and are common causes of fever, cough, pink eye, diarrhoea and sore throats. There has been previous evidence that adenoviruses have caused acute hepatitis but this was mainly in immunocompromised individuals.
As this current outbreak is so unusual, it is now increasingly likely that COVID-19 (SARS-CoV-2) is acting in combination with adenovirus to cause this acute hepatitis outbreak that so far, has only affected children.
What symptoms were experienced?
The cases identified showed significantly elevated liver enzymes and most cases reported symptoms such as abdominal pain, vomiting and diarrhoea and jaundice. These cases were tested for the most common viruses that cause acute hepatitis (A, B, C, D and E) but none of these was found. In addition, there has been no found link between travel or country-specific risk factors. Cases were found to have high levels of liver enzymes AST and ALT.
Were children positive for COVID-19?
In 74 of the cases, adenovirus was detected, identified as F type 41. In 20 cases of those who were tested, COVID-19 (SARS-CoV-2) was detected and in 19 further cases, adenovirus and SARS-Cov-2 co-infection were found. This suggests that both COVID-19 (SARS-CoV-2) and adenovirus are playing a significant role in causing severe acute hepatitis in these children.
In the UK, which has reported the most cases, a significant increase in adenovirus in the community has been detected. Adenovirus was previously at low levels, likely due to safety measures taken to prevent COVID-19 transmission.
What is the risk?
The UK was the first country to report an unexpected and significant increase in cases of acute hepatitis in children, all of whom were previously healthy and not immuno-compromised. This has now been reported in other countries. Although adenovirus is a contributing factor, it does not explain the severity of hepatitis.
The adenovirus identified (type 41) has not previously caused hepatitis or serious clinical pictures. It simply is not known as a cause of hepatitis in healthy children.
Further research is ongoing to look at the impact of COVID-19 (the vast majority of the affected children were not vaccinated) and other infection and non-infectious explanations.