words by Ruta Cakla
Not Just A Respiratory Disease: Recent Studies Highlight How COVID-19 Can Affect The Brain
A number of viruses such as the flu, Zika and rubella are known to affect the brain and thus lead to neurological symptoms that do not go away even after the patient has made a recovery from the viral infection. This prompts the question whether it is also the case for the virus that has been on our minds for a while. During the earlier stages of the covid-19 pandemic, scientists came out with such claims that coronavirus might cause brain haemorrhage, stroke, and memory problems. Now, two years later, enough time has passed to allow researchers to investigate this question in more detail. Indeed, as of recently, more neuroscientists are coming out with various findings linking the virus to potential neurological and mental health consequences.
For instance, experts have estimated that around a quarter of covid-19 patients experience depression within the early stages of being infected. As the illness progresses, it is likely to lead to brain fog, forgetfulness, or trouble concentrating in nearly half of the patients with long-term covid-19 symptoms, a survey done in the US reports. Another study analysing the medical records from more than 200 000 patients who had been infected, showed that approximately a third of the participants were diagnosed with a psychiatric or neurological condition within six months of recovery from the virus.
Interestingly, the neurological symptoms of long covid have been found to be similar to those that people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) might experience of the daily, state Spudich and Nath in their paper published in Science earlier this year. This is consistent with data from a survey conducted online, where the most common long covid symptoms six months after the infection were fatigue, cognitive dysfunction, and post exertional malaise (the worsening of symptoms after minimal physical or mental exertion). Furthermore, Spudich and Nath also stress that research into how long-term covid affects the nervous system might actually help with better understanding ME/CFS as the information available about these conditions is rather sparse.
There has also been some insight into why the coronavirus might cause such problems. Covid-19 seems to differ from other viruses such as HIV in a way that it does not directly damage the brain tissue. Rather, it has been suggested that the reason why covid-19 seems to have such significant effects on the nervous system, might be the virus’s impact on blood vessels reports Jessica Hamzelou to the New Scientist.
Autopsy studies have shown that covid-19 might cause the walls of blood vessels in the brain to become thinner, possibly leading to protein leakage out of the vessels, which may trigger the immune response. This idea is supported by the fact that research investigating the contents of the cerebrospinal fluid (CSF) in covid patients, found changes in the immune cells within the fluid, especially noting that a higher production of chemicals that can have toxic effects on brain cells was observed. Such findings have prompted researchers at Stanford University to compare the brain fog characteristic of long covid to neurological problems often seen in cancer patients, which are thought to be evoked due to the way that the immune system responds to chemotherapy.
However, everything might actually not be as bleak as it seems. Some neuroscientists have speculated that even though the impact of covid-19 to the nervous system can result in long-term aftereffects, there is no reason to believe that these cannot be reversible. Rather, according to the before mentioned researchers at Sandford, there is potential for developing effective treatments against the virus’s damage to the brain through research which can additionally help with further understanding of other conditions that affect the nervous and immune systems.