Acute hepatitis in young children of unknown cause has been reported one after another, mainly in Europe and the United States. It turned out that one child had died in Japan.

What are the symptoms? The latest analysis results are:

Here's what we've learned so far. (As of April 1)

One child dies in Japan

Acute hepatitis in children of unknown cause has been reported one after another since April last year, mainly in Europe and the United States.

According to a report by the WHO = World Health Organization in July last year, 7,1010 people, mainly in the United Kingdom and the United States, were reported to have symptoms, 5 people, or 46%, required a liver transplant, and 2 people, or 22%, died.

And one child had died in Japan, according to an announcement by the National Institute of Infectious Diseases.

According to the National Institute of Infectious Diseases, as of February 1, 2 cases of acute hepatitis of unknown cause had been reported in children, 16 cases required liver transplantation, and 156 cases required advanced treatment, such as admission to ICU = intensive care unit.

What kind of symptoms occur?

The symptoms were that in addition to a fever of 37 degrees for 5 minutes or more, there were many digestive symptoms such as abdominal pain, diarrhea, and vomiting.

In addition, there were symptoms of yellowing of the skin, coughing, white stool, and impaired consciousness.

The age of the patients ranged from 1 year 4 months to 9 years and 2 months, with a median age of 4 years and 6 months.

There is no gender difference between 54% of boys and 46% of girls. 25% had underlying medical conditions.

With acute hepatitis

What kind of disease is acute hepatitis?

The liver plays a wide range of roles, such as making proteins necessary for the body and storing nutrients, detoxifying harmful substances, and producing bile necessary for digesting food.

Acute hepatitis is a disease that affects both children and adults, and causes symptoms such as ▽ "udan", ▽ vomiting,
▽ general malaise,


▽ fever
.

According to the website of the National Center for Global Health and Medicine, depending on the type of hepatitis, it can deteriorate rapidly in about 1% to 2% of patients and may die.

Children can get hepatitis from a "tummy cold"

According to Dr. Hitoshi Tajiri of Yumura Clinic, who is familiar with liver disease in children, even children can develop hepatitis due to their decreased liver function during a so-called "tummy cold."

However, it means that symptoms may not appear very often, especially in infants.

If the cause of hepatitis is not clear, symptomatic treatment such as administering vitamins is used, and most of them improve in a short period of time, and there are usually few cases of worsening, but if "Oudan" worsens, the brain may be damaged, and if liver function is extremely reduced, it will not be possible to make proteins that stop bleeding, In rare cases, a liver transplant may be required.

Why "unexplained"

Generally, acute hepatitis is caused by five types of hepatitis viruses, from type A to type E. There are also alcoholic hepatitis and hepatitis caused by the consumption of drugs.

However, WHO experts say they have not found any hepatitis viruses, bacteria, poisons or drugs that are normally thought to cause hepatitis in children who develop symptoms.

For this reason, WHO has warned national health authorities of "acute hepatitis of unknown cause".

In response to this, the Ministry of Health, Labour and Welfare is asking local governments to check and report whether there are children up to 5 years old who had high liver enzyme levels in the test as far back as October 2021.

In addition, the "Japan Pediatric Liver Study Group," which consists of specialists who are familiar with children's liver disease, has also set up a research team to investigate detailed symptoms and causes.

Is the cause related to "adeno-associated virus"?

One year has passed since the report of hepatitis of unknown cause, but the exact cause is still unknown.

Until now, it has been pointed out that "adenovirus" causes sore throat and diarrhea.

According to the WHO, adenovirus was detected in 52 out of 368 cases, or 193% of European patients.

However, no conclusive evidence was found to clarify the cause, and the investigation continued.

In Japan, adenovirus has been detected in a total of 151 cases out of 16 people for whom information has been obtained.

New analysis results announced

Under such circumstances, remarkable research results are emerging.

On March 3, three research groups, including those from the United Kingdom, independently published their new analysis results in the British scientific journal Nature.

In both studies, "adeno-associated virus" related to "adenovirus" was detected in many patients.

Groups such as the University of Glasgow in the United Kingdom detected the adeno-associated virus in 32 out of 26 children who contracted hepatitis, 14 out of 13 in groups from the University of California in the United States, and 28 out of 27 in groups such as University College London in the United Kingdom.

In addition, groups such as University College London say they have detected another virus that is said to help the virus multiply in the body.

Both research groups simultaneously examined healthy children and children with diseases unrelated to hepatitis, and found that few adeno-associated viruses were detected in these children.

Originally, adeno-associated viruses are not supposed to cause serious illness, but groups such as the University of California have pointed out that infection with multiple viruses at the same time may affect hepatitis of unknown cause.

On the other hand, regarding the relationship with the new coronavirus, groups such as the University of Glasgow say that the proportion of children infected with the new hepatitis in the surveyed areas is lower than that of children in the region as a whole, and there does not appear to be a direct link between the new coronavirus and acute hepatitis.

In Japan, 15% of patients had been infected with the new coronavirus and 17% had been vaccinated against the new coronavirus. (Summary by the National Institute of Infectious Diseases)

Japan expert: "You don't have to worry about this information alone"

Professor Sotaro Mushiaki of the Department of Pediatrics, Nara Hospital, University, and chairman of the steering committee of the Japan Pediatric Liver Study Group, commented on the reported deaths, saying, "Traditionally, there have been about 10 to 15 children a year who require liver transplants due to acute hepatitis, and there are cases of death. Parents don't have to worry about this information alone."

On top of that, regarding the relationship between adeno-associated viruses that have been pointed out, he said, "This virus itself does not have strong pathogenicity, and I think that this is not a simple matter of direct cause, but further research is awaited. I would like to wait for the results of my research."