Severe COVID-19 refers to cases of the coronavirus disease caused by the SARS-CoV-2 virus that result in serious illness and complications. This can include respiratory failure, pneumonia, multi-organ failure, and death. Research in this area focuses on understanding the factors that contribute to severe cases of COVID-19, such as underlying health conditions, immune system responses, and genetic factors. Scientists are also studying potential treatments and interventions to improve outcomes for individuals with severe COVID-19, including the use of antiviral medications, immunomodulatory drugs, and supportive care measures. Understanding severe COVID-19 is critical for developing strategies to reduce the burden of the disease and improve patient outcomes.