What is the COVID-19 Mortality Rate?

Do we know how deadly COVID-19 really is?

Knowing the COVID-19 mortality rate would help folks get a better understanding of just how concerned they should be about this new disease that is quickly spreading around the world.

New modeling from the CDC puts the COVID-19 case fatality rate at 0.1 to 1%.

Unfortunately, the widely different numbers we are hearing might contribute to some of the confusion people already have about the SARS-CoV-2 virus.

What is the COVID-19 Mortality Rate?

In general, the mortality rate for a disease is “the measure of the frequency of occurrence of death in a defined population during a specified interval.”

Defined population?

That’s not how many people have the disease. That’s literally how many people there are in the place you are talking about.

Instead of mortality rate, right now, what we really want to be talking about is the case fatality rate.

“The case-fatality rate is the proportion of persons with a particular condition (cases) who die from that condition. It is a measure of the severity of the condition.”

Mortality Frequency Measures

Still, differences in defining the “population” or cases has lead to differences in reports of case fatality rates from the CDC and WHO.

“There is now a total of 90,893 reported cases of COVID-19 globally, and 3110 deaths.”

WHO Director-General’s opening remarks at the media briefing on COVID-19 – 3 March 2020

The WHO reports a case fatality rate of 3.4% for COVID-19, which they get by simply dividing the 3,110 deaths by the 90,893 reported cases.

“This crude CFR is high: for comparison, the CFR for seasonal influenza is 0.1%. However, as I will show below, this number is not a one-size-fits all, and is influenced by many factors. Please do not look at 3.4% as an indicator of your risk of dying from COVID-19!”

SARS-CoV-2 coronavirus case fatality ratio

The CDC, on the other hand, is using a method that factors in the idea that there are likely many more mild cases that haven’t been officially reported. That gets them a much lower case fatality rate rate of 0.1 to 1%.

Only more testing will get us a more accurate case fatality rate for COVID-19.
Only more testing will get us a more accurate case fatality rate for COVID-19.

Then there is the large study on COVID-19 case fatality rates that did include suspected and asymptomatic cases, Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China. They found an overall case-fatality rate (CFR) of 2.3%.

“Epidemiologists think and quibble in terms of numerators and denominators—which patients were included when fractional estimates were calculated, which weren’t, were those decisions valid—and the results change a lot as a result.”

COVID-19 Isn’t As Deadly As We Think

What do these numbers mean to you?

They might be easier to understand if you compare the case fatality rate of COVID-19 to some other diseases.

DiseaseCase Fatality Rate
Rabies99.9%
H5N1 bird flu60%
Ebola50%
MERS34%
H7N9 bird flu25%
SARS15%
Yellow fever15%
Tetanus13%
Diphtheria5-10%
1918 flu pandemic1-3%
COVID-19*0.1-3%
2009 flu pandemic0.1%
Seasonal flu0.1%
Measles0.1%
A high case fatality rate doesn’t tell the whole story. It is also important to understand how likely it is for a disease to spread and get a lot of people sick. And a reminder that many vaccine preventable diseases are quite deadly!

Fortunately, COVID-19 is near the bottom of the list, and as we get more and more data, it seems like the official case fatality rate will continue to drop.

Still, since it is spreading at pandemic levels, that means a lot of people will get sick and could die, especially those in high risk groups.

Older people and people with severe chronic health conditions are likely at higher risk COVID-19 infections.
Older people and people with severe chronic health conditions are likely at higher risk for COVID-19 infections.

*How many? It’s too early to tell, as we really don’t know what the real COVID-19 case fatality rate is yet.

“Practice everyday preventive behaviors! Stay home when sick. Cover coughs and sneezes. Frequently wash hands with soap and water. Clean frequently touched surfaces.”

Preventing COVID-19 Spread in Communities

That makes it important to take steps to try and slow down the spread of SARS-CoV-2, especially to people who are at high risk.

More on the COVID-19 Fatality Rate