According to current studies, the COVID-19 disease which is caused by the SARS-CoV-2 coronavirus comprises at least five different variants. These differ in how the immune system responds to the infection. Researchers from the German Center for Neurodegenerative Diseases (DZNE) and the University of Bonn, together with other experts from Germany, Greece and the Netherlands, present these findings in the scientific journal "Genome Medicine".

Use of the diabetes drug metformin - before a diagnosis of COVID-19 - is associated with a threefold decrease in mortality in COVID-19 patients with Type 2 diabetes, according to a racially diverse study at the University of Alabama at Birmingham. Diabetes is a significant comorbidity for COVID-19.

A clinical trial involving COVID-19 patients hospitalized at UT Health San Antonio and University Health, among roughly 100 sites globally, found that a combination of the drugs baricitinib and remdesivir reduced time to recovery, according to results published Dec. 11 in the New England Journal of Medicine.

Scientists at Sanford Burnham Prebys Medical Discovery Institute have identified the sensor in human lungs that detects SARS-CoV-2 and signals that it's time to mount an antiviral response. The study, published today in Cell Reports, provides insights into the molecular basis of severe disease and may enable new strategies for the treatment and prevention of COVID-19.

Seeking to understand why COVID-19 is able to suppress the body's immune response, new research from the USC Leonard Davis School of Gerontology suggests that mitochondria are one of the first lines of defense against COVID-19 and identifies key differences in how SARS-CoV-2, the virus that causes COVID-19, interacts with mitochondrial genes when compared to other viruses.

A novel computational drug screening strategy combined with lab experiments suggest that pralatrexate, a chemotherapy medication originally developed to treat lymphoma, could potentially be repurposed to treat COVID-19. Haiping Zhang of the Shenzhen Institutes of Advanced Technology in Shenzhen, China, and colleagues present these findings in the open-access journal PLOS Computational Biology.

COVID-19, which has killed 1.7 million people worldwide, does not follow a uniform path.

Many infected patients remain asymptomatic or have mild symptoms. Others, especially those with comorbidities, can develop severe clinical disease with atypical pneumonia and multiple system organ failure.