Over the past two years, lockdowns and mask-wearing measures to control the spread of COVID-19 have prevented these children from building immunity to adenoviruses, and with the lifting of restrictions, their exposure to the virus has had even more serious consequences
Photo/Visual China
Wen | Reporter Jiang Wei of Caijing
Editor| Haozhou
Following the discovery of acute hepatitis in children of unknown etiology in several European countries, the first suspected case was also reported in Japan. On April 25, Japan's Ministry of Health, Labor and Welfare said that a patient admitted to the hospital for treatment showed symptoms similar to acute hepatitis of unknown causes published by the World Health Organization.
According to information released by the World Health Organization on April 23, as of April 21, at least 169 cases of childhood acute hepatitis of unknown etiology have been detected in 12 countries. These countries are mainly distributed in Europe, of which 114 cases were reported in the United Kingdom, 13 cases in Spain, 12 cases in Israel, 9 cases in the United States, 6 cases in Denmark, 5 cases in Ireland, 4 cases each in the Netherlands and Italy, 2 cases each in Norway and France, and 1 case each in Romania and Belgium.
The age of patients varies from 1 month to 16 years, but most are under the age of 10 years, and most of them are under 5 years old. The outbreak of acute severe hepatitis has resulted in 17 people requiring liver transplants and has resulted in the death of one patient.
Jeffrey Lazarus, co-director of the Viral and Bacterial Infections Project at the Global Health Institute in Barcelona, told Caijing that there are still many uncertainties around this acute severe hepatitis, and the most worrying thing is the severity of the condition.
"It is likely that there are more cases, but they have not yet been detected, so it is very important for the health department to remain vigilant." Lazarus said. He previously worked in the European Office of the World Health Organization and is currently Vice-President of the International Liver Foundation of the European Society of Liver Disease.
Adenovirus is thought to be a potential cause
According to information released by the World Health Organization, patients showed clinical symptoms of acute hepatitis, with significantly elevated liver enzymes. Gastrointestinal symptoms such as abdominal pain, diarrhea, and vomiting occur in most cases, but the vast majority of patients do not develop fever symptoms. The common viruses that cause acute hepatitis have not been detected in any cases, and laboratory tests have ruled out hepatitis A, B, C, D, and E. Currently known information suggests that international travel or association with other countries is not the cause of this hepatitis.
Lazarus said it's not uncommon for hepatitis to be triggered by unknown causes, and it's hard to predict how much time it will take to determine the cause.
Although investigation into the cause is ongoing, current investigations indicate adenovirus as a potential cause. At least 74 patients were detected with adenovirus and 20 were infected with the novel coronavirus. In addition, 19 people were infected with both the novel coronavirus and the adenovirus.
"If it's related to COVID-19, I think there will be more children who test positive for COVID-19, but they may also have been infected before and then healed." Lazarus said. Of the six cases detected in Denmark, none of the patients tested positive for COVID-19 on post-admission tests, but one patient had contracted COVID-19 two months earlier.
Information released by the World Health Organization indicates a significant increase in adenovirus community infection in the UK, where cases are concentrated, and the Netherlands has reported the same situation. But this does not mean that the infection has only recently occurred, it is possible that the infection has been around for some time and has not been detected until recently with the increase in testing.
Although adenovirus is considered a potential cause, it fails to adequately explain the clinical phenomenon. Of the 74 patients detected for adenovirus, 18 were infected with adenovirus type 41. Symptoms of adenovirus 41 infection are usually diarrhea, vomiting, and fever, accompanied by respiratory symptoms, but most of these patients show no signs of fever. Although children with immunocompromise have contracted hepatitis at the same time as they are infected with adenovirus, adenovirus type 41 is usually not the cause of hepatitis infection in healthy children, and most of the children reported with this type of hepatitis in the UK are previously in good health.
There is no association with the COVID-19 vaccine
Mila Chander, director of clinical and emerging infections at the Uk Health Security Agency, introduced the relevant situation in the UK at the annual meeting of the European Society of Clinical Microbiology and Infectious Diseases on the 25th. She revealed that Scotland reported the first 5 cases on 31 March, and the sick children were not infected with known hepatitis from type A to E, which alerted doctors, who usually only see four or five cases of hepatitis of unknown etiology a year.
Chander said that the main hypothesis at this stage is that adenovirus works with co-factors. Of the cases found in the UK, 77% of patients are positive for adenovirus. In a statement on April 21, the UK Health Security Agency said the information gathered by the investigation was increasingly suggesting that the cases were linked to adenovirus infection. But adenoviruses typically exhibit not this pattern of disease, and they are investigating other underlying factors, including other infections or environmental causes.
The co-factor that ranked first was susceptibility, which is associated with an increase in common viral infections following the relaxation of COVID-19 restrictions. Over the past two years, lockdowns and mask-wearing measures to control the spread of COVID-19 have prevented these children from building immunity to adenoviruses, and with the lifting of restrictions, their exposure to the virus has had even more serious consequences.
Chandler said that during the spread of the new crown epidemic, the transmission rate of adenovirus in the UK has dropped significantly, but with the lifting of the new crown restrictions, the adenovirus is spreading in a range above the previous average.
Other possible co-factors include a previous history of COVID-19 infection and concurrent infection of COVID-19 and adenovirus. Scientists and clinicians are also investigating whether the genome of the adenovirus has changed.
No covid-19 vaccine has been reported in the UK, so this hepatitis outbreak is not considered to be associated with the COVID-19 vaccine.
Factors that need further investigation include increased susceptibility in children, potential new adenoviruses and complications of COVID-19, the World Health Organization said in a statement.
The World Health Organization first reported on 5 April this year that 10 cases of acute severe hepatitis had been detected in central Scotland, with symptoms including jaundice, diarrhoea, vomiting and abdominal pain, of unknown cause. The patients ranged in age from 11 months to 5 years, and none of them had any health problems before they developed the disease. One of them developed symptoms in January, while the remaining nine began in March.
