Nobody had ever seen the coronavirus that causes the disease known as COVID-19 before the current outbreak began in China in December 2019. So for context, it is often compared to a symptomatically similar disease we know well: the seasonal flu, which infects many people each year but kills only about 0.1% of them on average.
Many people were alarmed, then, when the World Health Organization announced in March that COVID-19 has killed 3.4% of the people who have caught it so far—a mortality rate far higher than not only the seasonal flu, but also higher than earlier COVID-19 mortality estimates, which were around 2%.
