Fact Check: Coronavirus now evolving to attack human brain?

The Covid-19 sub-variant fuelling the unprecedented rise in cases in China may be undergoing a scary change. As per researchers, this subvariant of coronavirus may be evolving to attack the brain. 

The new study by scientists is challenging assumptions that viruses become less dangerous as they evolve. Covid-19 may be changing the way to attack the human body and might increasingly make the brain its target instead of the respiratory system, the study reported by South China Morning Post said. However, the relevance to humans has not been proven by the study. 

The subvariant BA.5 behind the China surge caused much severe damage to brains of mice and cultured human brain tissues compared to the earlier BA.1 subvariant, researchers from Australia and France have said. The attack on the brain led to brain inflammation, weight loss and death, the China-based daily reported.

“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,” the research manuscript uploaded to preprint platform bioRxiv said.

“These results suggest that the Omicron lineage is not evolving towards reduced pathogenicity,” the team of researchers wrote.

The study is yet to be peer-reviewed and other virus experts have urged caution when reading the results. The mouse model used in the study has been highlighted by some as a major limitation, arguing that the results do not apply to humans. 

“They showed that all the mice died from brain infections of BA. 5, which is apparently very different from human infections that we know of," University of Hong Kong virologist Jin Dongyan said. 

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(With inputs from IANS)