[Text/Observer Network Wang Hui] The new crown epidemic has not yet ended, and a mysterious hepatitis suddenly appeared in many countries around the world, extending its "poisonous hand" to children.
As of now, more than 200 children in 17 countries around the world have been infected, and cases have been reported in the United Kingdom, the United States, Spain, Israel , France, Japan, etc. The current cases are mainly concentrated in Europe, with the UK having the largest number, which has increased to 145.
According to Richard Pebody, an infectious disease expert at the WHO European Regional Office, the patient is between 1 month and 16 years old, about 10% of the cases require liver transplantation and at least 1 death.
What makes many people afraid or even panic is that the cause of these hepatitis cases is still unknown and the investigation is underway.
Virology expert Chang Rongshan told Observer.com that according to his understanding, before COHK, hundreds of unexplained childhood hepatitis were found every year in China. The causes of these childhood hepatitis cannot be found in the cause of these childhood hepatitis, nor can it be completely attributed to infection. Therefore, more than 200 cases have been reported overseas, which is within the normal range, so there is no need to panic.
He believes that hepatitis in children is unlikely to cause a large-scale epidemic like the new coronary pneumonia. "Although the transmission of infectious diseases in the digestive tract is not as strong as that of respiratory infectious diseases, if it is prevalent, it will not be at this level. Thousands of cases are the minimum."
Chang Rongshan said that in the post-epidemic era, as more and more countries open their doors, there may be more and more unknown diseases in children in the future, and we need to pay great attention to it.
British child diagnosed with hepatitis due to unknown cause in March this year Source: Daily Mail
The "murderer" is adenovirus ?
Since all cases did not detect the five common hepatitis viruses, such as A, B, C, D and E, have not been detected in all cases, researchers from many countries have expanded the scope of virus screening to those viruses that do not fall within the routine testing of acute hepatitis, including enterovirus, varicella zoster virus, adenovirus, etc.
Finally, they found a new clue: adenovirus.
Among the 169 cases released by the WHO, 74 children tested positive for adenovirus, of which 18 were identified as adenovirus type 41 (Ad41). 20 children were detected in the new coronavirus, and 19 were co-infected with adenovirus and the new coronavirus.
On April 25, UK Health and Safety Authority (UKHSA) issued a technical briefing on the investigation. The briefing said that of 53 cases tested, 40 of them had adenovirus. Based on blood sample data, the initial typing of adenovirus is type 41, but other types of adenoviruses have also been found in non-blood samples. Before determining the viral properties, it is essential to perform whole genome sequencing of multiple cases . Although the low adenovirus content in the blood is a challenge to data quality, this work is still underway.
Data from the British medical and health department show that the current level of common virus transmission in children is currently higher than in previous years, and the number of cases of adenovirus infection in has increased significantly, especially in the group of children aged 1 to 4 years old.
England case pathogen test and results Source: Briefing of the UK Health and Safety Agency on April 25
The US Centers for Disease Control and Prevention released a report on April 29 showing that from October 2021 to February 2022, a total of 9 cases of acute hepatitis of children with unknown causes were reported in Alabama, USA. Before the onset, these patients had overall good health and had no confirmed records of COVID-19.
The center introduced that adenovirus was detected in all patients' blood samples. When samples from 5 of them were genetically sequenced, type 41 adenovirus was detected in all 5 samples.
adenovirus is a common human pathogen, a double-stranded DNA virus, without envelope, divided into 7 subgroups (A-G subgroups), with a total of 57 serotypes, mainly spread between people through respiratory tract and contact, and often causes respiratory diseases. Different serotypes of adenovirus may cause other diseases, such as gastroenteritis (inflammation of the stomach or intestinal tract), conjunctivitis (red eye), and cystitis.
41 adenovirus is a common cause of acute gastroenteritis in children. "Because the pathogenicity is weak and hepatitis rarely occurs. Liver transplants or even deaths in children like this are very rare," said Chang Rongshan.
Source: WeChat public account "Huashan Infection"
Since the symptoms of these childhood hepatitis cases are not typical symptoms of adenovirus infection, experts are still investigating other possible causes, such as new coronavirus infection or environmental factors.
Will Irving, a professor of virology at the University of Nottingham, UK, said adenovirus infection is a possibility, but it has not been confirmed. There are few cases of adenovirus infection related to hepatitis in children or adults with normal immunity in the global literature, so “if adenovirus infection is indeed found to be associated with this disease outbreak, it needs to explain why the natural history of adenovirus infection has changed so dramatically in 2022”.
The surge in hepatitis in children may be related to long-term blockade
After humans are born, there are two ways to obtain immunity. One is the passive immunization of obtained during natural infection/recovery, and the other is the active immunization obtained through vaccination.
Chang Rongshan said, "There is no vaccine for adenoviruses", so passive immunity can only be established through continuous contact.
In a briefing on the 25th, the UK Health and Safety Agency proposed a hypothesis that the increase in children's hepatitis cases in unknown causes may be a chain reaction of the new crown pandemic. Lockdowns and other restrictions mean that many children are exposed to less common viruses during the pandemic than normal, and as society reopens, they have insufficient immune responses in the face of infection.
"In order to prevent and control the new coronavirus, countries have adopted isolation policies, wearing masks, maintaining social distance, blocking the abortion between the international community, etc. This "blocking" has greatly cut off the transmission route of epidemics under normal circumstances, and the transmission level of adenovirus has also been reduced. Generally speaking, there are pre-stored antibodies to the serotypes of multiple human adenoviruses in adults. However, in recent years, the antibodies against human adenoviruses in children who rarely contact adenoviruses have been greatly reduced. Children under 5 years old generally lack passive immunity to adenovirus. Therefore, after the relaxation of countries in the northern hemisphere, within 2 months, in February-April every year, when the adenovirus epidemic is high, it is explained that some children were infected and ill." Chang Rongshan said.
September 2021, Madrid , a teacher is taking the temperature of students. Photo source: Associated Press
He believes that in the post- COVID-19 era, there will be many unknown infections in children. Because the long-term isolation policy has caused children not to be exposed to various respiratory viruses for a long time, which is not conducive to the development of the immune system and it is difficult to produce various pre-stored neutralizing antibodies that resist pathogens that are constantly encountered during the growth process.
"In this sense, the best way to prevent epidemics is vaccines," said Chang Rongshan. However, the two common viruses related to the respiratory tract, respiratory syncytial virus and adenovirus, have not had vaccines. It is expected that the epidemic intensity in children will increase in the future. Their mortality rate (Case Fatality Rate) in the children's population far exceeds that of the new crown CFR.
He called on all sectors of society to pay attention to viral pneumonia in children and to increase the research and development of infectious disease vaccines for children. For the biomedicine investment industry, this is a future blue ocean market. "As long as we use a small part of the venture capital to develop this type of vaccine, it can greatly reduce the harm of this epidemic to children." The
laboratory test results suggest that adenovirus may be related to childhood hepatitis due to unknown reasons, but other infectious diseases or environmental factors cannot be completely ruled out. Metagenome sequencing and sequence analysis are still in progress, and the results have not been announced.
A few days ago, Xie Youhua, director of the Department of Pathogen Biology, Professor of the Key Laboratory of Medical Molecular Virology, and Vice Dean of the Shanghai Institute of Major Infectious Diseases and Biosafety, and other experts wrote an article in the magazine "Microbiology and Infection", speculating that the possible causes of childhood hepatitis this time are as follows:
1, is a new variant of a known virus, which may be adenovirus, but the possibility of other pathogens cannot be ruled out, such as variant strains of coronavirus, rhinovirus , enterovirus, parainfluenza virus, etc. If it is a new variant of adenovirus, it is worth paying attention to whether it is related to the recombination and mutation of adenovirus under the selection pressure that may occur after large-scale vaccination of adenovirus vector vaccine.
2. The epidemic prevention and control during the 2019 coronavirus disease epidemic may cause some young children to reduce contact with common pathogens, resulting in the development of their immune system different from that of children of the same age before the 2019 coronavirus disease epidemic. When young children are subsequently infected with common pathogens such as adenovirus, they will produce immune responses or disease manifestations that are different from those of their previous peers; it is also possible that they will produce unusual immune responses or disease manifestations based on the previous SARS-CoV-2 (new coronavirus) infection, or if SARS-CoV-2 is co-infected with adenovirus or other viruses.
3. There is a new pathogen that has not been discovered yet.
4. Non-infectious factors, such as environmental toxins, drugs, etc., cannot be completely ruled out.
Are there any infection risks for children in our country? What should parents do?
As cases of childhood hepatitis in unknown causes were exposed in many countries, recently, news like "cases of childhood hepatitis in unknown causes appeared in Beijing" spread wildly on the Internet.
In response to various rumors, on the afternoon of April 27, the official Weibo of the Beijing Municipal Health Commission issued a statement saying that after verification by the Beijing Municipal Health Commission, there were no cases of unexplained childhood hepatitis and any deaths in Beijing.
Despite this, Xie Youhua and other experts still reminded that whether there are similar childhood hepatitis of unknown causes in my country still needs to be investigated. According to the confirmed case standards, the incidence of clinically unknown children's hepatitis in my country since January 1, 2022 (Henodes A, B, C, D, E has been excluded), and compared with previous years' data to analyze whether there is an increase in the number of hepatitis in my country. On the other hand, since the disease has an imported risk, it is necessary to prepare early. Considering the differences in immune backgrounds and prevalent pathogens in different countries and regions, it is not possible to evaluate the risk of disease caused by exposure to this pathogen in our children in my country.
As for personal protection, Chang Rongshan mentioned that the main methods to prevent adenovirus infection include: washing hands frequently, avoid touching eyes, nose and mouth with unclean hands, and avoiding close contact with patients.
He suggested that children should be widely vaccinated with the safe and effective new crown vaccine , such as recombinant protein vaccine , so that children aged 0-5 should take off their masks as soon as possible. "Otherwise, the child's immune system cannot develop normally. Attacks through various pathogens in the respiratory tract are an indispensable 'harvest' for children in their growth. Flowers in greenhouses are destined to not experience strong winds and rains. A small chance of infection falling on a child's head is a big stone."
Chang Rongshan said that at present, parents should remain calm and rationally look at various remarks on the Internet that link the rare disease to the new coronavirus. He said that has not yet reported direct evidence of acute hepatitis related to coronavirus infection. In addition, the WHO also reported that since most children have not received the COVID-19 vaccine, the assumption that acute hepatitis is related to the side effects of the COVID-19 vaccine is not supported at present.
According to the symptoms of the existing cases, parents should pay close attention to whether their children have these symptoms. Once discovered, they need to seek medical attention in time:
· Diarrhea, abdominal pain;
· Vomiting, nausea, and not wanting to eat;
· Discoloration of urine or feces;
· Usually accompanied by jaundice (the skin and white eyeballs are light yellow);
· Fatigue, pain in the liver area;
· Hemorrhage of gums while brushing teeth, and there are purple and purple bruises on the body;
· Itchy skin;
· liver enzyme significantly increased;
· Most children have no symptoms of fever.
