Why has there been an increase of hepatitis in children?

A rise in hepatitis in children

In 2022, 270 children under 10 years of age were diagnosed with hepatitis - inflammation of the liver - in the UK¹. This unusually high number of hepatitis in children caused the UK Health Security Agency (UKHSA) to jump into action to figure out the reason behind the outbreak.

There are many types of hepatitis in children, and these have various causes. Depending on the hepatitis type, this liver condition can be very treatable, but it can also sometimes be life-threatening. Most types - hepatitis A, B, C, D, and E - are caused by an infection with a virus. However, according to the UKHSA, these known hepatitis viruses have not been found in the children affected².

What caused the surge of hepatitis in children?

To cover all bases, healthcare officials have been investigating whether these cases of hepatitis in children could be linked to either a viral or non-viral form of hepatitis.

The UKHSA has explored three main theories:

1. This could be a new hepatitis-causing virus that hasn't yet been identified.

2. This could be an existing hepatitis virus, or existing viruses combining, causing new symptoms.

3. This could be non-viral - for example, hepatitis can be caused by toxins or medications.

For a while, the leading theory has been that infections of hepatitis in children caused by adenovirus could be to blame.

"Studies have found that all patients with unexplained hepatitis had high levels of adenovirus, a common virus that can spread from person to person, causing respiratory symptoms, vomiting and diarrhoea in children," explains Natasha North from British Liver Trust.

Adenovirus can occasionally also cause other serious infections. The COVID-19 pandemic has meant that children have been mixing less. Since 2022, children have been mixing more, and so certain infections, including adenovirus, have been circulating at a higher rate.

2023 research makes huge breakthrough

In March 2023, two scientific studies revealed that the rise in unexplained childhood hepatitis cases is linked to a virus called adeno-associated virus 2 (AAV2) - another common childhood virus that affects up to 90% of the population5, and that's similar in structure to adenoviruses.

The studies detected AAV2 in 81% and 96.4% of unexplained cases respectively - rates that were significantly higher than children who weren’t infected with hepatitis. This may suggest that AAV2 could directly cause this strain of hepatitis, but it could also be a more detectable biomarker of an adenovirus infection - which could also be the underlying cause.

The researchers also found that 93% of infected children carried a particular gene that affects the immune system. This suggests that some children may be genetically more vulnerable to this form of hepatitis.

Could there be a link with COVID-19?

In 2022, the COVID-19 virus was one of the possible infections under scrutiny. Some of the children who contracted hepatitis had recently been infected with COVID-19, although experts caution that this is to be expected given the high COVID-19 infection rates in this age group.

Experts also stress that there is no link between these incidences of hepatitis and the COVID-19 vaccine2. This is because no vaccinations were given to the children who were under 5 years of age - the age group which makes up over 75% of current hepatitis cases.

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Hepatitis in children - what is the advice for parents?

First and foremost, experts would like parents to know that the risk to public health is minimal. If your child develops the common mild symptoms associated with a viral infection - don't panic. The chance of them developing hepatitis is still extremely low.

They recommend the following precautions:

• You don't need to contact the NHS unless your child is very unwell. For example, if they have trouble breathing, if they are not eating or drinking, or if they develop jaundice (yellowing of the eyes or skin).

• If your child's symptoms are rapidly getting worse or you are worried, contact your GP or, if in the UK, call the NHS on 111.

• Children who are unwell should be kept at home and shouldn't go to school or nursery.

• Children with gastrointestinal symptoms - including vomiting and diarrhoea - should remain at home until 48 hours after the symptoms have passed unless they have any of the worrying signs above.

Far from a national issue

The UK has been just one of 34 countries experiencing a rise in unexplained hepatitis in children⁶. However, we do know that this outbreak is unrelated to the 2022 hepatitis A cases in the USA - these have been connected to contaminated strawberries that were imported from northern Mexico to California between March and April 2022, leading to 18 confirmed cases as of 5th July.

Further reading

1. GOV.UK "Hepatitis (liver inflammation) cases in children - latest updates".

2. UK Health Security Agency (UKHSA) "An increase in Hepatitis Cases in Children".

3. World Health Organization (WHO) "Hepatitis A".

4. World Health Organization (WHO) "Hepatitis B".

5. The University of Edinburgh: Study provides insight into child hepatitis outbreak.

6. World Health Organization (WHO) "World Hepatitis Summit 2022 urges action to eliminate viral hepatitis as unexplained hepatitis cases in children rise globally".