Over the new year weekend, many news reports cited a study conducted by researchers in Australia warning of a more 'dangerous COVID variant' that was found to be 'fatal to the brain'.
On 2 January, the Central Government put out a fact-check, saying, the claims are misleading because the "relevance to humans has not been proven by the study."
Does this mean the study itself is misleading? Here's what the study really says.
The study's aim was to find out if the pathogenicity – the virus' ability to infect and cause disease – of the COVID variant BA.5 reduced over time.
According to the authors, SARS-CoV-2 is known to lose its pathogenicity over time. However, they say, "The increased level of immunity in human populations makes it difficult to distinguish between reduced intrinsic pathogenicity and increasing protective immunity."
The first authors are from Berghofer Medical Research Institute, Brisbane, and Clem Jones from Centre for Ageing Dementia Research, Queensland Brain Institute.
Key findings of the study:
Isolated BA.5 Omicron variant was found to be more pathogenic in mice.
BA.5 also infected human cortical brain organoids to a greater extent than other Omicron variants.
The researchers concluded that the findings suggest that the BA.5 Omicron variant shows increased neurovirulence compared to earlier omicron sub-variants.
Between the lines: Now the study itself is in the pre-print stage, and is yet to be peer-reviewed, which means its findings are yet to be corroborated.
Moreover, the study authors themselves underscore in the paper that the study has its limitations, and that further research would be needed to confirm them.
Some of the shortcomings of the study are:
The study was conducted on mice, and human cortical brain organoids created in vitro. Not in humans.
The pathogenicity of the variant in question was tested on a group that was not exposed to other variants before.
What this means is that we don't know if the pathogenicity of the variant would be just as robust in vaccinated populations that have been infected before.
So, we don't know if the higher rate of disease noted in vitro would necessarily translate to a notable threat in the real world.
The big picture: BA.5 was first detected in India in mid 2022, and has been around for a while. Since then researchers have been closely studying it along with other dominant sublineages of Omicron. So far there has been no conclusive evidence to suggest that BA.5 causes more severe illness than previous variants.
That COVID-19 can cause neurological damage is known, but if this particular variant could cause significantly worse damage to the brain than other COVID variants cannot be said just yet.
The bottomline is that the study complies with the scientific process, and presents an important starting point to work from. However there is a long way before its real world implications are established.
In the meantime, jumping the gun with sensationalist headlines like 'New variant attacks brain', and, 'variant fatal for brain', can fuel uncalled-for public alarm.
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