Various measures or rates have been used to understand the chances of COVID-19 causing death. The most common measure that has been used is the “case fatality rate (CFR).” It asks the question: "Out of everyone we're measuring who is confirmed to have had this disease, how many have died?"

This rate is not constant. It changes with time, population, location, and treatment available, among many other factors.

Case fatality rate is an important metric. However, in the case of COVID-19, it may not give an accurate measure of the risk of death. That is because it accounts only for confirmed cases and deaths. There may be many undiagnosed people with COVID-19 who never make it into official data. Excess deaths that may have occurred due to COVID-19 are not counted if those people were not tested for COVID-19. Asymptomatic cases of COVID-19 that go unnoticed and untested may also skew numbers.

In fact, the case fatality rate is only as good as the number of tests conducted. If one is not tested, they are not counted. So lack of testing can impact the accuracy of this number.

Case fatality rates for COVID-19 have varied from 0.1% in some countries to more than 10% in other countries, according to data from Johns Hopkins.

The clinical trials of major COVID-19 vaccines show that people who are vaccinated against COVID-19 have highly reduced risks of falling severely ill from COVID-19. Chances of hospitalization and death due to COVID-19 drop significantly in vaccinated people, data shows. As an example of real-life effectiveness, a study conducted in Israel showed that as vaccine coverage increased in the country, there was a decline in the cases of COVID-19 infection.

Some people have questioned whether COVID-19 is a pandemic at all because of its low mortality rate and high contagion. A pandemic is defined as a disease that is spreading worldwide or over a wide area, crossing international boundaries and impacting a large number of people. This assessment is based on the spread of disease. It is not determined by the number of deaths or severity of illness. The WHO declared COVID-19 a pandemic on March 11, 2020.

Using one mortality rate to describe the impact of the pandemic around the world would not make for an accurate description of the situation. The number of confirmed COVID-19 deaths per million varies a lot from location to location, and depends on many factors. It also keeps changing over time. To give a comparative picture of the impact of the disease, the estimated case fatality rate (CFR) for SARS-CoV is 10%. Seasonal flu's case fatality rate in the U.S is about 0.1 to 0.2%, according to available data.