Dear Reader:

Case Fatality Rate (CFR) number= what percentage of infected people die from the infection, or said in other words, it is the number of fatalities divided by the number of confirmed infections (times 100). For the following diseases, the CFR’s are- seasonal flu: 0.1%,  the Spanish flu pandemic of 1918-1920: 2%-3%, or 4%, or 10%, SARS (caused by a coronavirus, SARS-Cov) of 2002-2003: 10%, MERS (caused by a coronaviurs, MERS-Cov) of 2012- present: 34%, current SARS, estimate by WHO in March: 3.4%.

www. virology. ws is a website with hundreds of blogs “about viruses and viral disease”. In this website,  Dr. Vincent R. Racaniello, a Higgins Professor in the Dept of Microbiology at Columbia University’s College of Physicians and Surgeons, one of four virologists who recently authored Principles of Virology, a textbook used by many teaching virology to medical students, wrote on his March 5 blog (www. virology. ws/ 2020/ 03/ 05/ sars- cov- 2- coronavirus- case- fatality- ratio):

“the CFR is not a one-size-fits all…this ‘crude’ global CFR for COVID-19 .. which is 3.4%… 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!… data from the COVID-19 outbreak in China we know that age has a substantial impact on CFR. Based on a summary of 44,672 cases earlier in the outbreak (published by China CDC Weekly), no child between 0-9 years of age died of infection; and in individuals less than 50 years of age, the CFR is less than 1%. Only in older individuals does the CFR increase. The CFR also varies by country, likely due to differences in the standard of care. ..South Korea.. CFR of 0.4%!.. in Italy and in Iran the CFR so far is 3.1%. These differences are not due to circulation of different viruses in these countries, but a combination of the quality of health care available and the age of the patients… I do think that we are missing many infections, not just in China but in other countries, and therefore the CFR may be even lower. There are likely many individuals with mild respiratory symptoms (typical in the winter) who are infected but never diagnosed. Only well after this outbreak is over, when serological studies are done to determine the extent of infection, will we have an accurate CFR. I am not attempting to minimize the seriousness of SARS-CoV-2 and COVID-19: there will certainly be many infections in the US and there will be deaths due to the infection. However, please understand that a CFR of 3.4% does not apply to everyone; what happens to you if infected depends on your age, health status, and where you live.”

Wikipedia in its very long, updated and very impressive (includes colorful graphs and visuals) entry on “Coronavirus disease 2019”, states: “in those younger than 50 years, the risk of death is less than 0.5%, while in those older than 70 it is more than 8%”, and it includes a graph with the title “Covoid-19 fatality rate by age” it details the following CFR’s by age groups:

14.8% for 80 and over,     8% for 70-79,      3.6% for 60-69,     1.3% for 50-59,      0.4% 40-49,    0.2% 10-29.

anita