An outbreak of hepatitis cases in young children could be linked to a common virus, British disease experts think, as more cases are confirmed.
In the past five days, two more young patients in the UK have needed liver transplants.
The outbreak, which is mostly hitting children under five, began in the UK, spread to Europe and the US and, on Tuesday, Japanese doctors confirmed what is believed to be the first case in Asia.
The UN health agency has received reports of at least 169 cases of “acute hepatitis of unknown origin”. One death has been recorded. The UK has recorded 111 cases.
While it is not clear what’s causing the spike in liver illness among children, a leading suspect is adenovirus, which was detected in 75 per cent of the confirmed cases tested, the UK Health Security Agency said.
Adenovirus is a common group of viruses, now circulating in children at higher-than-average levels after dropping to unusually low levels during the pandemic.
There are also concerns children may have lower immunity levels as a result of Covid-19 lockdowns that meant children spent less time playing together and more time social distancing.
“Information gathered through our investigations increasingly suggests that this rise in sudden onset hepatitis in children is linked to adenovirus infection,’’ said Dr Meera Chand, director of clinical and emerging infections at the HSA.
“However, we are thoroughly investigating other potential causes.
“We may not have seen as much of it as we have for the past couple of years,” she said.
“But we have a co-factor affecting a particular age group of young children, which is either rendering that infection more severe or causing it to trigger some kind of an immunopathology.”
The HSA has recorded 111 cases of unexplained hepatitis in children under 10 since January. Ten of the children needed liver transplants.
Most of the cases of liver inflammation were in children under five, although a small number of cases in children over 11 are also being examined.
Of the confirmed cases, 81 live in England, 14 are in Scotland, 11 are in Wales and five are in Northern Ireland.
The cases are predominantly in children under five who showed initial symptoms of diarrhoea and nausea followed by jaundice.
The number of children who have required a liver transplant has risen to 10 in the UK. There have been no deaths, the UKHSA added.
The cases have not been caused by the usual viruses that cause hepatitis A to E, and data gathered has “increasingly” suggested the rise in severe cases of hepatitis may be linked to a group of viruses called adenoviruses, the agency said.
Of 53 cases tested, 40 (75 per cent) showed adenovirus was the most common pathogen detected. A total of 16 per cent of cases, meanwhile, were positive for Covid-19, which was not unexpected due to the high rates of the virus during January to April this year.
The agency said there is no link to the coronavirus vaccine as none of the currently confirmed cases in under 10s in the UK are known to have been vaccinated.
Routine NHS and laboratory data show common viruses circulating in children are currently higher than in previous years and there is a marked increase of adenovirus, particular in the one to four age group, it added. Further work is under way to investigate the link between adenovirus and these cases.
Adenovirus is a family of common viruses that usually cause a range of mild illnesses — including colds, vomiting and diarrhoea — and most people recover without complications.
While they do not typically cause hepatitis, it is a known rare complication of the virus.
Adenoviruses are commonly passed from person to person and by touching contaminated surfaces, as well as through the “respiratory route”.
