Researchers at Amsterdam’s UMC teaching hospital have found evidence for what many scientists have suspected, that coronavirus does appear to have an impact on the brain via the immune system.

The research, published in The Lancet medical journal, is based on autopsies carried out on 21 people who died with or from coronavirus. It found that the disrupted immune system of critically ill COVID-19 patients causes damage to all organs, and most notably, the brain.

The virus itself was not found in the brains of the people in the study, but the researchers did find evidence that the immune system of the patients had attacked certain proteins in the brain while fighting off coronavirus.

‘We could see that immune cells of the innate non-specific immune system in particular were seriously disrupted,’ researcher Marianna Bugiani said in a press release. ‘The immune cells that would normally have done their job after a few days remained highly active in patients and caused brain damage.’

The fact that the immune system reacts so strongly shows that it makes sense to give drugs that suppress the immune response to Covid-19 patients, Bugiani said.

‘The activity in the brain maybe the cause of the loss of sense of smell and the long-lasting loss of concentration that many people report. But we don’t know yet,’ pathologist Paul van der Valk said.