Immune reactions to severe Covid may trigger brain problems, study finds

According to research, covid infections can cause immune reactions that damage nerve cells in the brain, causing memory problems and confusion, and raising the risk of long-term health issues.

Preliminary findings show that Covid can cause neurological problems in patients without the virus having to enter the brain. The process may contribute to brain fog and other problems experienced by people with long Covid.

The hope is that our research can help identify which treatments would be most appropriate to diminish or prevent these symptoms.

In the first wave of the Pandemic, blood from 36 Covid patients were analysed. They found that the levels of IL 6 were more than fifteen times higher than normal in people who had been exposed to the disease.

Covid patients with delirium have a state of extreme confusion that can leave people not knowing who or where they are. The patients had higher levels of IL 6 than other Covid patients. More than a third of Covid patients are admitted to the hospital with delirium.

The scientists exposed lab-grown nerve cells to the patients' blood in order to see how high levels of IL 6 might affect the hippocampus. Blood from patients with delirium increased the death rate of brain cells. Damage is thought to cause delirium.

There was a cascade of events that led to the harmful effects. The impact of the proteins on generating new brain cells was found to be profound.

The scientists reported that blocking the proteins protected brain cells. The work suggests that drugs that calm immune reactions to Covid may be able to fight delirium.

Older people are more vulnerable to delirium than younger people. A rise in the risk of dementia is caused by confusion.

The delirium symptoms in acute Covid patients and the neurological symptoms in long Covid patients are believed to be caused by the proteins. She said that it could help personalize their treatment.

Increased inflammation has been shown to have a direct effect on brain cells which are linked to delirium and memory problems. The reduction in repair mechanisms could explain why people with delirium have cognitive problems.

The same immune reaction may contribute to the brain fog some Covid patients report. Confirmation will need to come from further work, such as the Covid-CNS study, which is investigating 800 UK patients who had neurological or neuropsychiatric complications from Covid.