Cases of hepatitis in children have increased as a further 43 illnesses were confirmed by the UK Health Security Agency (UKHSA) today.
Eight of the 108 cases have received a liver transplant. There are 14 cases in Scotland, 79 in England with the rest in Wales and Northern Ireland.
Since January, a rise of cases of sudden onset hepatitis (liver inflammation) in children aged 10 and younger has been under investigation.
It comes as experts exploring recent hepatitis cases said that less mixing during the pandemic could be a possible factor for the recent rise.
Public Health Scotland epidemiologist Dr Kimberly Marsh said in the report that children could be 'immunologically naive' to the virus due to restrictions during the pandemic.
Meanwhile, the UKHSA said the the investigation continues to point towards a link to adenovirus infection as 77 percent of cases tested were positive for the virus.
Adenoviruses is a group of common viruses that cause a range of illnesses and cold-like symptoms.
The agencies investigating the cases are the UKHSA, Public Health Scotland, Public Health Wales and the Public Health Agency.
The UKHSA wrote: "However, as it is not usual to see this pattern of disease from adenovirus, we are actively investigating other possible contributing factors, such as another infection (including COVID-19) or an environmental cause."
The agency confirmed that there is no link to Covid vaccine - none of the children are known to have been vaccinated.
It added that the UKHSA is also investigating whether there has been a change in the genome of the adenovirus.
Dr Meera Chand, Director of Clinical and Emerging Infections at UKHSA, added: "Normal hygiene measures such as thorough handwashing (including supervising children) and good thorough respiratory hygiene, help to reduce the spread of many common infections, including adenovirus.
"We are also calling on parents and guardians, to be alert to the signs of hepatitis (including jaundice) and to contact a healthcare professional if they are concerned."
Are lockdowns connected to the rise of hepatitis cases in kids?
Less mixing during the pandemic is a possible factor, according to a paper published in the journal Eurosurveillance on April 14.
Epidemiologist Dr Kimberly Marsh of Public Health Scotland was the lead author of the paper that looked into the rise of hepatitis cases.
One theory is that hepatitis is having a greater impact on "immunologically naïve children", said the article.
It says: "At the time of publication, the leading hypotheses centre around adenovirus — either a new variant with a distinct clinical syndrome or a routinely circulating variant that is more severely impacting younger children who are immunologically naïve.
"The latter scenario may be the result of restricted social mixing during the COVID-19 pandemic.
"Adenovirus infection as a cause of severe hepatitis is rare in immunocompetent children but has been reported in case reports and series."
Hepatitis symptoms
According to the NHS, signs of hepatitis can include:
- muscle and joint pain
- a high temperature
- feeling and being sick
- feeling unusually tired all the time
- a general sense of feeling unwell
- loss of appetite
- tummy pain
- dark urine
- pale, grey-coloured poo
- itchy skin
- yellowing of the eyes and skin (jaundice)
Don't miss the latest news from around Scotland and beyond - sign up to our daily newsletter here .