Doctors and scientists at the UK Health Security Agency (UKHSA) are investigating 74 mystery cases of children hospitalised with hepatitis. Hepatitis is a condition that affects the liver and may occur for a number of reasons. However, in the cases under investigation, the common viruses that cause hepatitis have not been detected, officials said. Public health doctors and scientists are examining 49 cases in England, 13 in Scotland and 12 across Wales and Northern Ireland. All have occurred since January. Several possible causes are being investigated, UKHSA said. One active line of inquiry is whether or not a group of viruses called adenoviruses may be causing the illnesses. Adenoviruses usually cause a range of mild illnesses and most people recover without complications. They can cause a range of symptoms, including colds, vomiting and diarrhoea. While they don’t typically cause hepatitis, it is a known rare complication of the viruses. Other potential explanations are also being investigated, including whether or not Covid-19, other infections or environmental causes may have played a role in the spate of cases. However, officials stressed that there is no link to Covid-19 vaccines because none of the children affected have had a vaccine. Dr Meera Chand, director of clinical and emerging infections at the UKHSA, said: “We are working swiftly with the NHS and public health colleagues in Scotland, Wales and Northern Ireland to investigate a wide range of possible factors which may be causing children to be admitted to hospital with liver inflammation known as hepatitis. “One of the possible causes that we are investigating is that this is linked to adenovirus infection. However, we are thoroughly investigating other potential causes. “Normal hygiene measures such as good handwashing, including supervising children, and respiratory hygiene, help to reduce the spread of many of the infections that we are investigating. 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.”