How big is the impact of the unexplained childhood hepatitis that has been all over the news recently?

||||

Written by reporter Lai Tianying

Interview experts

Tian Siyuan (Deputy Chief Physician, Liver Intervention Department, Nantong Cancer Hospital, Jiangsu Province)

▲12 countries reported acute pneumonia in children of unknown cause (Photo from CCTV.com)

Recently, the increase in cases of acute hepatitis of unknown origin among children has attracted global attention. The World Health Organization said that at present, there have been at least 169 cases of hepatitis in children worldwide, including one death. In the UK alone, 114 children have been infected, 10 of whom need liver transplants.

According to reports, the first cases of this unexplained hepatitis appeared in the UK in April, and the infected people were usually healthy, young children. On April 25 local time, the UK Health and Safety Agency stated that adenovirus may be the cause of this unexplained hepatitis.

Mira Chand, director of clinical and infection specialists at the Health Security Agency, said that information collected by health department investigations increasingly suggests that the increase in acute hepatitis in children may be related to adenovirus infection, but other potential causes cannot be ruled out.

▲Mira Chand shares the latest survey on unexplained childhood pneumonia in the UK (Photo from The Paper)

So, what is adenovirus? Is the unknown hepatitis related to the COVID-19 vaccine? Are children in my country at risk of infection? Let's take a look.

☼ ☼ ☼

Adenoviruses that affect the respiratory system can also affect the liver

Adenovirus, or HAdV for short, was first isolated from adenoids and tonsils of children removed during surgery in 1953. Subsequently, the same virus was isolated from the secretions of patients with respiratory diseases. It was officially named in 1956 and divided into seven subgroups from A to G. More than 90 genotypes have been discovered so far.

▲The appearance of adenovirus under a microscope and its structural model (picture from "Medical Microbiology (8th Edition)")

Studies have found that 4% to 10% of pneumonia is caused by adenovirus infection, especially children under 5 years old are susceptible to infection. In the past, respiratory infections caused by adenovirus were mainly sporadic cases, but there have also been small-scale local epidemics or large-scale epidemics. For example, there was a large outbreak of adenovirus in the barracks of new recruits in the United States, which was brought under control after the use of vaccines. After the vaccine was discontinued in 1999, the epidemic reappeared. In 2007, there were adenovirus outbreaks in four states in the United States, with a mortality rate of about 4%. In the 1960s, there was a pandemic of adenovirus pneumonia in infants and young children, with a high mortality rate. Since then, there have been many small-scale local epidemics.

When a reporter from Beijing Science and Technology Newspaper interviewed Tian Siyuan, deputy chief physician of the liver intervention department of Nantong Cancer Hospital in Jiangsu Province, Tian Siyuan said that adenovirus infection mainly induces the host's nonspecific natural immune response, causing edema, congestion, and necrosis of the bronchial and bronchiolar mucosa, increased mucus secretion, and airway obstruction. In severe cases, it can damage elastic fibers, cartilage, and smooth muscles, leading to persistent lung function damage. There are dozens of common adenoviruses that can be transmitted from person to person. In addition to the respiratory system, adenoviruses can also affect the central nervous system, circulatory system, and blood system, causing colds, conjunctivitis, gastroenteritis and other diseases.

▲Adenovirus can affect various organs of the human body (Picture from The Paper)

At present, adenoviruses have been isolated from almost all human organs. Therefore, the possibility of adenovirus infection causing hepatitis exists. Cases of adenovirus-induced hepatitis have been reported before, but they are mostly seen in children with weak immune systems.

On April 25, the UK Health and Safety Agency revealed that among 53 cases of acute childhood hepatitis of unknown cause, 40 (75%) patients were detected to contain adenovirus. However, the UK Health Agency stated that other types of adenovirus were also found in non-blood samples of patients. Before the characteristics of the virus can be confirmed, whole genome sequencing must be performed on multiple cases.

Dr. Meera Chand, director of clinical and emerging infectious diseases at the UK National Health Service, also said that the information collected through our investigation shows that children with unexplained acute hepatitis may be related to adenovirus 41 infection, but they are also investigating other potential causes. Meera Chand said that parents and guardians should be vigilant about unexplained acute hepatitis.

☼ ☼ ☼

Unknown hepatitis and COVID-19 vaccination have not yet been proven to be related

Some COVID-19 vaccines use adenovirus as a vector, so many people are worried whether this unknown hepatitis is related to the vaccination? The public health department has made a special clarification: unknown hepatitis has nothing to do with the COVID-19 vaccine. The UK Health and Safety Agency said that in almost all cases so far, none of the children had received the COVID-19 vaccine.

The Italian Higher Institute of Health also released an in-depth research report on the pediatric hepatitis of unknown cause that has recently appeared in Europe, the United States and other countries, saying that there is currently no evidence of a link between the disease and the new crown vaccination, and that the connection between the two can be ruled out after considering multiple factors.

The institute said that in almost all cases so far, the children had not been vaccinated. The study also considered the hypothesis that adenovirus caused hepatitis, as proposed by some researchers, to be extremely unlikely.

In its risk assessment, the World Health Organization pointed out that adenovirus is currently considered a hypothesis for the cause, but this cannot fully explain the severity of clinical symptoms. Other influencing factors, such as the reduced level of adenovirus transmission during the COVID-19 pandemic, the increased susceptibility of young children, the possible emergence of a new type of adenovirus, and simultaneous infection with SARS-CoV-2, also need further study.

In addition, in almost all cases so far, the children who fell ill had not been vaccinated, and the hypothesis of side effects of the new crown vaccine is not supported at present. The World Health Organization is closely monitoring the situation and cooperating with relevant parties such as the British health authorities.

☼ ☼ ☼

Maintain good hygiene habits - no need to panic for Chinese children

On April 25, the Ministry of Health, Labor and Welfare of Japan announced that a case of unexplained childhood hepatitis was also found in Japan. Following the recent reports of multiple cases of unexplained childhood acute hepatitis in many European and American countries, this suspected local case reported by Japan is the first in Asia.

So, with the high incidence of unexplained hepatitis cases, are children in my country at risk of infection? And how can we prevent it?

According to the Greek China-Greece Times, in response to the recent cases of unexplained hepatitis in children, Martina Pagoni, president of the Piraeus Medical Association in Athens, Greece, called for strict compliance with hygiene measures and said that hepatitis is an infectious disease and its spread needs to be controlled through certain means.

Martina stressed that there is no need to panic because hepatitis treatment methods and methods are currently mature. "Parents need to pay attention to whether their children have symptoms of hepatitis, such as vomiting and diarrhea and other gastrointestinal disorders. If they find any, they should contact the pediatrician immediately. Everyone should strictly follow hygiene measures because hepatitis is contagious."

Zhu Jieye, director of the Department of Hepatobiliary Surgery at Peking University People's Hospital, said in an interview with the media that "unexplained hepatitis" refers to clinical liver inflammation that cannot be clearly diagnosed through conventional methods. Generally speaking, to determine preventive measures, we must first identify its specific transmission route. For example, hepatitis A is mainly transmitted through the "digestive tract", so to prevent hepatitis A, we must pay attention to food hygiene; hepatitis B is mainly transmitted through blood, and cutting off the transmission route is one of the main means of preventing hepatitis B.

Are children in my country at risk of infection? "Children in my country are currently required to receive immunizations for hepatitis B and A. The incidence of hepatitis in children in China is very low. As for hepatitis of unknown cause, I have not heard of such cases in China. However, as long as it is an infectious disease, conventional means such as washing hands frequently and paying attention to cleanliness and hygiene are still effective in preventing infection," said an expert from the Qingdao Municipal Center for Disease Control.

Tian Siyuan also said that the World Health Organization is actively looking for the culprit of the disease, and there is no need to panic because of unknown hepatitis. In the vast majority of known cases, the damaged liver will regenerate and repair itself, and death is still a rare case. Children should pay attention to maintaining basic hygiene in daily life, such as washing hands frequently, which will help reduce infections from most common viruses and bacteria including adenoviruses.

The World Health Organization also said in a communiqué that before the pathogen is identified, more cases of this type of hepatitis are predicted to occur in the future, and called on all parties to "identify, investigate and report potential cases that meet the case definition."

In response to this, the Beijing Municipal Health Commission also issued a "Notice on Strengthening the Treatment of Cases of Unexplained Childhood Hepatitis" with the aim of reminding relevant medical institutions to be vigilant and pay attention to children with hepatitis of unknown causes. If such cases occur, the causes should be identified as soon as possible and treatment should be strengthened.

(Source: CCTV News, Xinhua News Agency, The Paper, Shangguan News, China News Network, Jiemian News, Health World, Health Times, New Evening News, Nan Fang Daily, Science Popularization China, etc.)

Produced by: Science Central Kitchen

Produced by: Beijing Science and Technology News | Beijing Science and Technology Media

Welcome to share to your circle of friends

Reproduction without authorization is prohibited