The Scientist: Why Some COVID-19 Cases Are Worse than Others

Image: CDC/Dr. Fred Murphy

Like many other respiratory conditions, COVID-19—the disease caused by SARS-CoV-2—can vary widely among patients. The vast majority of confirmed cases are considered mild, involving mostly cold-like symptoms to mild pneumonia, according to the latest and largest set of data on the new coronavirus outbreak released February 17 by the Chinese Center for Disease Control and Prevention.   

Fourteen percent of confirmed cases have been “severe,” involving serious pneumonia and shortness of breath. Another 5 percent of patients confirmed to have the disease developed respiratory failure, septic shock, and/or multi-organ failure—what the agency calls “critical cases” potentially resulting in death. Roughly 2.3 percent of confirmed cases did result in death.  

Scientists are working to understand why some people suffer more from the virus than others. It is also unclear why the new coronavirus—like its cousins SARS and MERS—appears to be more deadly than other coronaviruses that regularly circulate among people each winter and typically cause cold symptoms. “I think it’s going to take a really, really long time to understand the mechanistic, biological basis of why some people get sicker than others,” says Angela Rasmussen, a virologist at Columbia University’s Mailman School of Public Health.  

In the meantime, the latest data from China and research on other coronaviruses provide some hints.