Source 丨21 Healthnews21 original work
Author 丨 Wei laughs
Editor 丨Xu Xu
Picture 丨 Figure worm
Recently, several countries around the world have reported cases of hepatitis in children of unknown etiology. On 23 April, the World Health Organization issued its latest notification: since the UK reported the detection of 74 cases of acute hepatitis of unknown origin in children on the 15th, more countries have reported new cases.
As of 21 April, at least 169 cases of unexplained acute hepatitis in children have been reported in 11 countries in the WHO European Region and 1 country in the Region of the Americas. All cases ranged in age from 1 month to 16 years. Seventeen children (about 10 percent) needed a liver transplant and at least one died.
On April 21, local time, the latest report from the British health department said that the investigation showed that 34 new cases of hepatitis of unknown cause were found in the United Kingdom, bringing the total number of cases to 108. Of these cases, eight children underwent liver transplants because of their serious condition. According to the UK Health Security Agency, 77% of cases test positive for adenovirus. Survey data are becoming increasingly clear that this (hepatitis) is associated with adenovirus infection.
Professor Lu Hongzhou, head of the first public health expert group on epidemic prevention and control in Shenzhen and president of the Third People's Hospital of Shenzhen, pointed out to the 21st Century Business Herald that adenovirus is a very common virus, which is mainly transmitted through respiratory droplets and eye secretions through the respiratory tract or contact.
It is worth noting that Lu Hongzhou pointed out that in fact, all ages are susceptible to adenovirus, but because children's immune systems are not well developed and their resistance is poor, they are more susceptible to infection. In addition, infection with adenovirus does not generally cause severe acute hepatitis, but in immunocompromised patients can cause occasional or severe viral infections, especially in some organ transplant patients.
So, will this virus bring harm to the mainland? Lu Hongzhou pointed out that after the emergence of a new pathogen, its pathogenicity still needs to be carried out a lot of basic and clinical research. It is worth noting that the virus is also transmitted through the respiratory tract, but European and American countries because of the liberalization of epidemic prevention and control policies, do not require mandatory wearing of masks, so it will lead to the spread of the virus, but the mainland is different, at present, everyone still wears masks every day, so the possibility of transmission through the respiratory tract is relatively small, and it should not be too nervous at present.
Unexplained hepatitis or associated with adenovirus infection
According to the WHO, the first children were all located in the UNITED Kingdom and were found while hospitalized, with the earliest case being in January this year.
The U.S. investigation set a new time record. According to STAT, the United States has identified 9 cases of unexplained acute hepatitis in children, all reported by Alabama, with children ranging in age from 1 to 6 years. The earliest case was admitted to the hospital in the fall of 2021.
As of 12 April, there have been no deaths in various countries, but some children are very ill, with 6 Children in the Uk (6/74), 1 Spanish child (1/3) and 2 CHILDREN in the US (2/9) requiring liver transplants.
In the UK, children are concentrated in 2-5 years of age, and the main symptoms are vomiting, jaundice and yellowing of the whites of the eyes. The earliest batch of clinical data released by local researchers in Europe Monitor on April 14 showed that most children had blood levels of alanine transaminases (ALT) exceeding 2,000 IU/L, while normal values should be 10-40 IU/L.
The WHO report also indicates that the clinical syndrome in these cases is characterized by acute hepatitis, markedly elevated aminotransferases, usually with jaundice and sometimes with gastrointestinal symptoms.
Will Irving, a professor of virology at the University of Nottingham, believes that this situation is extraordinary, cases of hepatitis in children under 10 years of age are very rare, and adults are generally more likely to develop severe liver disease, while children are usually not affected.
Notably, just a week before the onset of illness, the children were healthy, and clinical records indicate that the children did not have any significant past medical history, such as underlying immunodeficiency or treatment with immunosuppressants.
However, the cause of this hepatitis is not yet clear. Hepatitis A, B, C and E virus infection was ruled out after several typical hepatitis virus tests were performed on children in the UK and Spain. Because most children do not have fever or abnormal markers of blood inflammation, C-reactive proteins, and elevated white blood cell counts, only a small percentage of children are bacteriologically tested and no abnormalities are reported.
After that, the scientists further expanded the detection range of viruses to those that are not within the scope of routine detection of hepatitis, such as enterovirus, paraintestinal virus, human herpesvirus 6, 7, varicella zoster virus, adenovirus. Eventually, they found that 5 of the 13 Scottish children published in Europe Surveillance tested positive for adenovirus, and officials from the Alabama Department of Public Health in the United States also confirmed in interviews that 5 of the 9 sick children in the local area were positive for adenovirus-41.
Meanwhile, UK Health Security Agency data shows that 77% of cases test positive for adenovirus. Mira Chand, who heads clinical and emerging infections at the UK Health Safety Service, noted that survey data are increasingly revealing that this (hepatitis) is linked to adenovirus infection. However, we are thoroughly investigating other possible factors.
The WHO said it strongly recommends that countries identify, investigate and report potential cases that meet the definition. The so-called "conformity to the definition" includes 3 aspects.
First, the confirmed case, i.e. after 1 January 2022, aged 10 years and below, has acute hepatitis (not caused by A, B, C, D or E virus infection) and aspartate aminotransferase (AST) or alanine transaminase (ALT) > 500U/L. In contrast, the normal ALT value should be 10-40 IU/L.
Second, the suspected case, i.e. after 1 January 2022, aged 11-16 years, with acute hepatitis (not caused by A, B, C, D, or E virus infection) and AST or ALT > 500U/L.
Third, epidemiologically related cases: after 1 January 2022, there was acute hepatitis (not caused by A, B, C, D or E virus infection) and had close contact with the confirmed case.
Why are children mostly affected and acute hepatitis common?
Lu Hongzhou pointed out that adenovirus is a very common virus, and there are 52 species of human adenovirus. In general, it is mainly transmitted through respiratory droplets and eye secretions through the respiratory tract or contact; intestinal infections are mainly transmitted through the digestive tract.
What are the dangers of adenovirus infection? Lu Hongzhou said that adenovirus can infect the respiratory tract, gastrointestinal tract, urethra and bladder, eyes, liver and so on. Typical symptoms of respiratory infection with adenovirus are cough, nasal congestion and pharyngitis, accompanied by fever, chills, headache and muscle pain, including 4 different syndromes: acute febrile laryngitis, pharyngeal conjunctival fever, acute respiratory disease and pneumonia. Mild eye infections caused by adenovirus are a complication of respiratory tract infections and laryngitis, and corneal and conjunctivitis can occur. Invasion of the gastrointestinal tract can cause gastroenteritis in infants and children under 4 years of age, causing abdominal pain and diarrhea. Others can cause acute hemorrhagic cystitis in children, cervicitis in women, and urethritis in men.
As a seasonally transmitted virus, February to April is the peak of adenovirus epidemic. The WHO statement noted that an increase in adenovirus transmission activity was observed in the UK during the same period as the above-mentioned child cases were reported.
Why are there many children? Lu Hongzhou pointed out that in fact, all ages are susceptible to adenovirus, but because children's immune systems are not well developed and their resistance is poor, they are more susceptible to infection. "Many adults may have been infected with adenovirus, so they can produce certain antibodies, and the symptoms are mild."
Adenovirus is a common virus that causes respiratory infections in children, and about 4% to 10% of pneumonia is caused by adenovirus infection. Notably, adenovirus pneumonia is one of the more severe types of community-acquired pneumonia in children. Some children are more severely ill, often with complications such as pharyngeal conjugate membrane fever, enteritis, encephalitis, pneumonia, cystitis, etc., which is one of the important causes of death and disability of infant pneumonia at present.
Will Irving, a professor of virology at the University of Nottingham in the United Kingdom, said that during the new crown virus epidemic, children in isolation at home had less contact with external pathogens and their immune function was neglected. After the relaxation of the new crown epidemic prevention, children resumed classes and social activities, and the possibility of contracting the virus increased significantly. This includes adenovirus infection.
Why do most children develop acute hepatitis? In this regard, Lu Hongzhou also pointed out that under normal circumstances, infection with adenovirus does not cause severe acute hepatitis, but in immunocompromised people can cause occasional or serious viral infections, especially in some organ transplant patients, serious respiratory infections and viral hepatitis.
Some experts pointed out that although mild hepatitis in children is quite common, this time the situation is significantly different, and some patients in the UK are in serious condition, and some even need liver transplants. Adenoviruses rarely cause severe hepatitis in healthy people. It is very rare for this to occur in children who do not have serious underlying health problems. The UK health department is actively researching other possible contributing factors, such as another infection (including COVID-19) or environmental causes.
"European Surveillance" also pointed out that if the above-mentioned acute hepatitis in children is indeed caused by adenovirus infection, it is either a new variant with a unique clinical syndrome or a routinely circulating adenovirus strain, but it has a more serious impact on children with low immunity. The latter scenario may be the result of restricting social interaction during the COVID-19 pandemic.
It is worth noting that in addition to adenovirus infection, scientists have also noticed that some children have recently tested positive for new crown, and the variant strain circulating during this time period is mainly Omilon BA.2. Models from the Uk's Office for National Statistics estimate that the proportion of children aged 2-4 who test positive for SARS-CoV-2 in the country was about 7% in early February, reached around 13% in mid-March and fell to 7% in early April.
Further investigations are currently underway by UK authorities, including a more detailed history of exposure, toxicological testing, more comprehensive virological/microbiological testing, and organizing experts to conduct a thorough investigation of the suspected case.
The WHO proposes that the priority now is to identify the cause to guide further clinical and public health actions. Any epidemiological link between cases may provide indications for tracing the source, and the spatiotemporal link between cases and possible risk factors in their contacts should be carefully investigated.
How to prevent it correctly?
In fact, there is no need to worry too much. Amy Feldman, medical director of the Pediatric Liver Transplant Division at Colorado Children's Hospital, noted that while the above cases are important, parents should not pay too much attention to it, "there is no need to think about insomnia." This week, my daughter threw up and pulled. But I definitely wouldn't worry about her liver failure. That's too rare. ”
Lu Hongzhou pointed out that adenovirus infection is mainly endemic in winter and spring, and it is easy to erupt in kindergartens, schools and other places. According to the characteristics of transmission, preventive measures are similar to the prevention of infectious diseases of other respiratory and digestive tracts: mainly wash hands frequently, disinfect frequently, and avoid contact with patients and their respiratory droplets. Usually drink more water, eat more vegetables and fruits, pay attention to exercise; indoor ventilation, keep the indoor environment clean; try to go to crowded public places as little as possible during the winter and spring epidemic seasons, wear masks when going out, and avoid contact with patients to prevent infection.
Once the symptoms of acute fever, sore throat and conjunctivitis occur, it is necessary to go to the hospital as soon as possible, isolate early, and treat early. In the case of a collective illness of more than 5 people, medical personnel should report to the epidemic prevention department in their area in a timely manner, and take effective prevention and control measures in a timely manner to avoid the spread of the disease. During the adenovirus epidemic season, young children with upper respiratory tract infections should go home and rest in isolation to avoid spreading the epidemic. After illness, try to see a nearby hospital and avoid infusion in the observation room of a large hospital with a large concentration of patients to prevent cross-infection. Severe cough and dyspnea are mostly severe cases, and you should go to the hospital in time to avoid delaying the condition.
It is worth noting that Lu Hongzhou pointed out that relevant basic and clinical research is still needed to determine how pathogenic it is. The virus is also transmitted through the respiratory tract, but European and American countries because of the liberalization of epidemic prevention and control policies, do not require mandatory wearing of masks, so it will lead to the spread of the virus, but the mainland is different, at present, everyone still wears masks every day, so the possibility of transmission through the respiratory tract is relatively small, and it should not be too nervous at present.
In addition, does the current domestic adenovirus vector vaccine against COVID-19 have protective efficacy against the virus? Lu Hongzhou pointed out that the adenovirus vector vaccine uses the modified harmless adenovirus as the carrier, loaded with the S protein gene of the new crown virus, and made into an adenovirus vector vaccine to stimulate the body to produce antibodies. "Although the adenovirus used in the adenovirus vector vaccine is not the same as the adenovirus, it should also have a certain immune cross-protection effect."