Avoid Covid-19 if you can. Your brain may thank you.

Friday, 11 March 2022

Dr Siouxsie Wiles is a microbiologist and associate professor at the University of Auckland.

OPINION: One of the problems with following all the Covid-19 studies is that by the time they are peer-reviewed and published in a scientific journal, it’s not clear how relevant they are to the latest variant. This is especially frustrating when it comes to studies about the potential long-term impacts of Covid-19.

As a case in point, the results of a very worrying study have just been published in the prestigious journal Nature. Researchers from the UK and the US took advantage of the UK Biobank to see whether a Covid-19 infection resulted in any changes to people’s brains as suggested by some Long Covid symptoms.

The UK Biobank is a massive biomedical database that contains in-depth genetic and health information from half a million participants living in the UK. Looking at data up to May last year, the researchers identified 785 UK Biobank participants aged 51–81 whose brains had been scanned before and after the pandemic started.

Of those, 401 people had tested positive for Covid-19. Just 15 had been hospitalised, so most people had what would be classed as mild to moderate disease. On average there was about a three year gap between people’s two scans. For those participants who tested positive, their second scan was roughly four to five months after they got Covid-19.

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Dr Siouxsie Wiles: “Artificial intelligence played an important part in discovering a potential new antibiotic. But it couldn’t have done it without the data generated from the enormous amounts of work put in by the researchers.”

As I said earlier, the results are really worrying. The researchers found that the people who tested positive for Covid-19 had a bigger reduction in the thickness of their grey matter in the regions of their brain associated with smell and some forms of memory. There was also evidence of tissue damage in the part of the brain linked to smell and in the cerebellum.

The cerebellum is linked to cognition and, sure enough, the people who tested positive for Covid-19 also took longer to answer questions in standard cognitive tests, evidence of a greater cognitive decline.

These results held true even when the data from the 15 people who had been hospitalised was removed. Also, analysing data from a small group of UK Biobank participants who had experienced non-Covid-19-related pneumonia showed the changes were specific to Covid-19.

In other words, even a mild to moderate Covid-19 infection was enough to impact the brain.

Here are some of the questions I’m left with. First, because the study uses data from May 2021, it only covers people who got Covid-19 before delta became dominant and before vaccines were widely available.

So, do delta and omicron cause the same level of damage to the brain? Will the damage improve or get worse as people age? Is it reversible? Does it happen to people under 50?

And the biggest question of all, what about if you’ve been vaccinated and get Covid-19? Does being boosted help?

Only time will tell, which is why I despair that some people just want to catch Covid now and “get it over with”. Mask up. Scan. Open doors and windows to get fresh air circulating.

Get tested and isolate if you are sick. Please. Your brain may well thank you later.