Long Covid ‘brain fog’ may be due to leaky blood-brain barrier, study finds

If barrier controlling substances entering and exiting brain is off balance, it can drive changes in neural function

From forgetfulness to difficulties concentrating, many people who have long Covid experience “brain fog”. Now researchers say the symptom could be down to the blood-brain barrier becoming leaky.

The barrier controls which substances or materials enter and exit the brain. “It’s all about regulating a balance of material in blood compared to brain,” said Prof Matthew Campbell, co-author of the research at Trinity College Dublin.