evidence: The measure that best describes the lethality of an infectious disease is the infection fatality ratio (IFR). The IFR indicates the proportion of people who die from a disease among all the people infected, including both confirmed cases as well as undetected infections. According to their respective IFR estimates, COVID-19 is at least ten times more deadly than an average flu season, particularly for middle-aged and elderly people. Furthermore, the lack of effective treatments or vaccines for COVID-19, along with potential long-term damage to survivors, make COVID-19 a serious health threat.