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.
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.”
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%.
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.
|Disease||Case Fatality Rate|
|H5N1 bird flu||60%|
|H7N9 bird flu||25%|
|1918 flu pandemic||1-3%|
|2009 flu pandemic||0.1%|
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.
*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
- How to Self-Quarantine After Being Exposed to a Disease
- Should You Be Tested for COVID-19?
- COVID-19 Hype or Hazard
- What You Need to Know About a COVID-19 Vaccine
- Risk Communication about Containment – 2019 Novel Coronavirus
- Past Time to Tell the Public: “It Will Probably Go Pandemic, and We Should All Prepare Now”
- SARS-CoV-2: Could it be bad?
- Beating the evolving COVID-19 pandemic – unprecedented human collaboration in discovery and innovation
- TWiV Special: Coronavirus SARS-CoV-2 and COVID-19 update
- CDC – Mortality Frequency Measures
- CDC – Preventing COVID-19 Spread in Communities
- SARS-CoV-2 coronavirus case fatality ratio
- WHO Director-General’s opening remarks at the media briefing on COVID-19 – 3 March 2020
- Covid-19 — Navigating the Uncharted
- Study of 72,000 COVID-19 patients finds 2.3% death rate
- Clinical Characteristics of Coronavirus Disease 2019 in China
- Characteristics of and Important Lessons From the Coronavirus Disease 2019 (COVID-19) Outbreak in China Summary of a Report of 72 314 Cases From the Chinese Center for Disease Control and Prevention
- COVID-19 Isn’t As Deadly As We Think
- Coronavirus Myths and Facts
- MMWR – Tetanus Surveillance — United States, 2001–2008
Last Updated on August 22, 2020 by Vincent Iannelli, MD