Taipei-Doctors at Taipei’s Tri-Service General Hospital have identified a mutation in an Omicron subvariant which they believe may have been behind a string of acute encephalitis cases in pediatric COVID-19 patients earlier this year.
From April to June, Taiwan experienced a surge of Omicron cases, during which doctors reported seeing a high incidence of children with neurological symptoms including encephalitis, or swelling of the brain.
To date, 206 cases of severe COVID-19 among children aged 12 and under have been reported in Taiwan, of which 31, or around 15 percent, have involved encephalitis, Central Epidemic Command Center (CECC) data shows.
To investigate this phenomenon, doctors at the Tri-Service General Hospital used whole genome sequencing and amino acid mapping to study data from six pediatric COVID-19 patients who developed severe encephalitis in May 2022.
In the study, the results of which were published this month in the International Journal of Infectious Diseases, they found that all the cases belonged to the Omicron BA.2.3.7 lineage.
However, the cases also had a specific S protein mutation — K97E — which differed from all other BA.2.3.7 lineage strains, possibly pointing to a distinct “node” of the subvariant, according to the study.
From this, they concluded that this new mutation in the S protein, which had not been observed in Taiwan before March, may explain the sudden increase in neurological symptoms in young COVID-19 patients at that time.
At a press conference on Wednesday, Tri-Service Hospital pediatrics specialist Chang Chia-ning (張佳寧) said the location of the K97E mutation is related to the COVID-19 virus’ replication process, and may impact immune regulation, though more research is needed to determine the exact cause and effect relationship.
In the study, for example, the team noted that all of the patients had high cytokine and inflammation markers, while testing negative for viral particles in their cerebrospinal fluid.
This suggests that the children’s severe neurological symptoms may have been caused by “hyperimmune states,” rather than the direct viral invasion of the central nervous system, the study said.
At the press conference, the team also noted that the K97E mutation does not appear in the BA.5 variant that is currently dominant in Taiwan, possibly indicating why child encephalitis cases have dropped off in recent months.
Source: Focus Taiwan News Channel