That research—examining deaths out of the total number of infections, which includes unreported cases—suggests that Covid-19 kills from around 0.3% to 1.5% of people infected. Most studies put the rate between 0.5% and 1.0%, meaning that for every 1,000 people who get infected, from five to 10 would die on average.

The estimates suggest the new coronavirus is deadlier than the seasonal flu, though not as lethal as Ebola and other infectious diseases that have emerged in recent years. The coronavirus is killing more people than the deadlier diseases, however, in part because it is more infectious.

“It’s not just what the infection-fatality rate is. It’s also how contagious the disease is, and Covid is very contagious,” said Eric Toner, an emergency medicine physician and senior scholar at Johns Hopkins Center for Health Security, who studies health-care preparedness for epidemics and infectious diseases. “It’s the combination of the fatality rate and the infectiousness that makes this such a dangerous disease.”