The wide variation of symptoms found in COVID-19 patients is due to SARS-CoV-2, the virus responsible for coronavirus disease. This virus can cause symptoms ranging from a benign infection to death. The article from National Institutes of Health describes why certain people develop severe COVID-19 symptoms. Researchers from the from the COVID Human Genetic Effort found that many of their 660 patients with severe COVID-19 have rare genetic variants in genes responsible for defense against the flu. 3.5% of these patients were completely missing a functional gene. Also, researchers from the National Institutes of Health found that among 1000 patients with life threatening COVID-19 pneumonia, 10% produce autoantibodies. Autoantibodies are malfunctioning antibodies that target a person's own tissues and organs instead of antigens. They also discovered that these autoantibodies are responsible for blocking type I interferons, a set of proteins that protects our cells and body from viruses. This blockage stops these patients from producing enough type I interferons to fight off SARS-CoV-2. I do think it's encouraging to hear that we're learning more about this virus everyday. Also, reading and learning about some of the reasons why certain groups are more likely to get severe COVID-19 was also a bit alarming. People may think that they're not at risk of severe COVID-19 because they're healthy. But, if they have one of these rare gene variants or produce autoantibodies, they have a high risk of getting severe COVID-19.