Is the mutant virus "BA2.3.7" the culprit of severe encephalitis in children? "1 mutation" can easily induce immune storm
The culprit diagnosed with encephalitis in young children! New coronavirus variant strain “BA2.3.7”
Is the culprit of severe encephalitis in young children diagnosed with the new coronavirus in Taiwan actually a previously undiscovered mutant virus “BA2.3.7”? The Tri-Service General Hospital held a press conference today (14th) and stated that during the previous wave of epidemic peaks from April to June, some sick children progressed rapidly and even developed “blast encephalitis”. Through the complete genome sequencing of viral strains of severely ill children, the Third General Administration of Public Health discovered that a mutant branch of the virus carries a new mutation site, K97E, which may be the key cause of encephalitis in children.
As of September 10 this year, there have been a total of 206 severe cases and 31 deaths among children under 12 years old in Taiwan. In severe cases, intraoperative encephalitis accounted for 31 cases. This shows that the epidemic in children from April to June was rapid and violent when vaccination was not widely available. situation.
In order to find out the potential causes of illness in the confirmed children, the Department of Pediatrics, Clinical Pathology and Genomics Center of the Tri-Service General Hospital analyzed the specimens of six critically ill children and found that the virus strain uploaded at that time was different from other virus strains that had been named at that time ( BA2.3.1-2-3-4-5-6) is the first time in the world that the causative mutant virus strain has been found for children infected with the new coronavirus and acute encephalitis.
K97E mutation site may induce immune storm and cause acute encephalitis
Director Wang Zhihong of the Tri-Service General Hospital said that the BA.2.3.7 virus mutant strain has a mutation site on the spike protein that is different from previous mutant viruses - K97E, which may make the virus more likely to interfere with the immune system of the infected person. This can then induce an immune storm and evolve into acute encephalitis, or a systemic inflammatory disease.
Dr. Chen Xizhou, director of the Pediatric Department of the Third General Hospital and an expert in pediatric neurology, pointed out that from April to June, the severely ill children admitted to the Third General Hospital ranged in age from 1 to 18 years old (the oldest child patient was 17 years old). Abnormal increases in various inflammatory indices indicate that the systemic immune system is being highly stimulated and activated, and there is no previous history of neurological diseases.
Half of severely ill children found abnormal mutation sites in spinal fluid affecting virus replication
Zhang Jianing, the attending pediatrician at the Tri-Service General Hospital, said that although there have been reports of cases of confirmed encephalitis in children since last year, the BA2.3.7 virus strain was first discovered in Asia, and the virus strains uploaded in Taiwan and Japan are highly homologous. All have common mutation sites.
It was found that no virus was cultured from the brains of sick children admitted to the hospital, indicating that the virus may not have entered the brain. It is inferred that the mutation site K97E affects the ability of the virus to replicate, thereby triggering an immune storm and causing “blast encephalitis” in young children.
Dr. Chen Xizhou said that cytokine-induced immune storms were found in more than half of children diagnosed with severe illness, and 50% of them showed abnormalities in spinal fluid. Therefore, the Pediatric Medical Association urgently announced guidelines for handling confirmed severe illness. Most children can successfully control their condition after taking immunomodulatory drugs, antiviral drugs and monoclonal antibody drugs. In the future, it is necessary to continue to study whether Taiwanese people have inherited genes that lead to an increase in the proportion of explosive encephalitis after diagnosis.
After vaccination, the proportion of children with encephalitis dropped by BA.5 and became the mainstream strain, which should not be ignored
Zhang Jianing pointed out that vaccinations for adolescents and infants were gradually opened from May to mid-July. Recently, the proportion of confirmed encephalitis in children has dropped significantly, and no large number of children have been repeatedly infected so far. However, the mainstream virus strain has recently been replaced by BA.5. Once a severe child case is confirmed, genetic testing and analysis will be conducted to help early detection of whether the virus has evolved new mutation sites.
Dr. Zhang Jianing reminded that the mRNA vaccine administered to children has good safety and protection. Currently, the virus continues to mutate, and the speed of vaccine development cannot keep up with the mutation of the virus. Parents and children should wear masks, wash hands frequently, and get vaccinated according to the recommendations of the command center. Even if you are infected, there are still some antibodies that can reduce symptoms and risk of severe illness.
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