How does coronavirus reach brain? What causes long Covid? Scientists find answer

Coronavirus can spread to many organs in the body starting from the airways, which is primarily the reason why people experience long Covid, a new study by the scientists at the US National Institutes of Health has revealed, Bloomberg reported. The findings have been described as the most comprehensive so far about the persistence of the virus in the body and brain.

According to the study, it takes time in getting rid of the virus completely and, in the meantime, the virus travels from one organ to another and that is why long Covid sufferers complain of symptoms affecting organs beyond the respiratory system.

In the study, researchers found persistent SARS-CoV-2 RNA in multiple parts of the body, including regions throughout the brain, for as long as 230 days after Covid symptoms were initially found.

For this study, the tissues taken during autopsies on 44 patients who died after contracting the coronavirus during the first year of the pandemic in the US have been widely studied. Patients with long Covid symptoms were not studied in the study though the findings shed light on why some Covid patients reported symptoms in organs that are not generally affected by Covid.

"For a long time now, we have been scratching our heads and asking why long Covid seems to affect so many organ systems. This paper sheds some light, and may help explain why long Covid can occur even in people who had a mild or asymptomatic acute disease," said Ziyad Al-Aly, director of the clinical epidemiology centre at the Veterans Affairs St. Louis Health Care System in Missouri, who has led separate studies into the long-term effects of Covid-19.

The findings have been released online in a manuscript under review for publication in the journal Nature.

So which are the organs where the virus can travel? The highest burden of the virus is in the airways and the lungs. But it can infect cells throughout the entire body, including the brain.