The dizzying amount of information about COVID-19 released every day makes it difficult to keep track of the latest findings. Understanding how and when this information was discovered as well as what questions have yet to be answered is a useful way to get a handle on the emerging science.

2020

January

• January 11: Wuhan health officials publish the genetic sequence of the novel coronavirus, SARS-CoV-2, which causes COVID-19. The virus is revealed to be a member of the betacoronavirus family that includes SARS and MERS-CoV.  Other betacoronaviruses have previously been shown to act on the nervous system.
• January 24: A Chinese study characterizing features of 41 coronavirus patients is published in The Lancet. Myalgia, or fatigue, is described as one of the most common symptoms, reported by 44% of patients.

March

• March 20: Forbes magazine reports that doctors in Germany and Italy have discovered a loss of taste and smell in their coronavirus patients.

April

• April 3: The first case of meningitis (inflammation of the membranes surrounding the nervous system) and encephalitis (inflammation of the brain) associated with the SARS-CoV-2 virus is reported in Japan.
• April 9: Scientists map out the distribution of the ACE2 receptor in the human brain. (Note: At the time of publication, this study is still a preprint and thus has not been peer-reviewed.) The ACE2 receptor had previously been established as the virus’ target for cell entry.

May

• May 4: Italian neurologists report demyelination (loss of myelin, the fatty matter that insulates nerve cells) in a coronavirus patient.

July

• July 8: British scientists publish a study of 43 coronavirus patients with neurological symptoms. Of the patients, twelve experienced nervous system inflammation, ten experienced encephalopathy accompanied by delirium or psychosis, eight suffered a stroke, eight had complications in the peripheral nervous system, seven developed Guillain Barré Syndrome, one developed plexopathy (pathology in a cluster of nerves), and five experienced some other symptom.
• July 29: The first case report of a patient with no family history of psychosis developing brief COVID-19-related psychotic symptoms is published by American scientists.

December

• December 27: A study of an international cohort of “long-haul” coronavirus patients reveals that the most common symptoms reported after six months were fatigue, post-exertional malaise, and cognitive dysfunction. (Note: At the time of publication, this study is a still preprint and thus has not been peer-reviewed.)
• December 30: In a letter to the editor of the New England Journal of Medicine, American scientists describe microvascular injury found in post-mortem studies of the brains of COVID-19 patients.

2021

January

• January 5: Scientists from UT Health in San Antonio publish a literature review of existing coronavirus research, suggesting that the neurological manifestations of COVID-19 may be due to the body’s immune response to the virus rather than the virus itself.