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Coronavirus: Omicron BA.5 subvariant may cause more damage – not less: study

  • The coronavirus subvariant surging in China may be evolving to attack the brain, researchers say
  • The study challenges previous assumptions that viruses usually evolve to become less dangerous

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A coronavirus subvariant surging in China may be evolving to attack the brain, researchers say. Photo: EPA-EFE
Ling Xinin Beijing
New research on the Omicron subvariant of the coronavirus has suggested the pathogen could be changing how it attacks the human body – shifting from infecting respiratory systems to increasingly targeting the brain.
Researchers from Australia and France found BA.5 – the coronavirus subvariant driving what is now the world’s biggest surge of infections in China – did much more severe damage to mouse brains and cultured human brain tissues than the previous BA.1 subvariant, leading to brain inflammation, weight loss and death.

The findings challenge the common belief that viruses usually evolve to become less pathogenic.

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“Compared with BA. 1, we found that a BA.5 isolate displayed increased pathogenicity in K18-hACE2 mice with rapid weight loss, brain infection and encephalitis, and mortality. In addition, BA.5 productively infected human brain organoids significantly better than BA. 1,” a manuscript of the research said.

The manuscript has been uploaded to the preprint platform bioRxiv, and will receive peer review for publication.

“These results suggest that the Omicron lineage is not evolving towards reduced pathogenicity,” wrote the team, which was led by virologist Andreas Suhrbier from the QIMR Berghofer Medical Research Institute in Queensland, Australia.

However, other experts have sounded a note of caution, noting that a major limitation of the study was the mouse model it had used, which they said probably did not apply to human beings.

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