Putting Case Fatality Rates in Perspective-and how we evaluate risks

I have been working on some family history documentation. My grandparents lived through the 1918-1919 Spanish Flu pandemic – I have posted some relevant quotes from my grandmother’s diary, about living through that pandemic.

My own Mom had Scarlet Fever in 1934. In 1900, Scarlet Fever is reported to have had a case fatality ratio up to 25% in some areas. I do not know the CFR for 1934.

As a child, I had only two immunizations for disease: Smallpox and polio. That is all that was available then. Today, children in the U.S. will be vaccinated against 14 to 17 separate diseases.

As I child, I had measles, mumps and chicken pox, all of which are now largely eliminated in western nations with vaccines. As a teen I had a systemic Staph A infection, untreated for 6 months, and ultimately combined simultaneously with influenza and pneumonia.

I was surprised to learn that the case fatality rate for measles, the year I had it, was 2.1%. – and measles was about one order of magnitude more contagious than Covid.

(Update: After I wrote this I talked to my doctor about my non-existent vaccination record. I had a serology test for MMR and it showed that I had had measles but not rubella. Consequently, in March of 2021, at age over 60, I finally received an MMR vaccination.)

The CFR for mumps and chicken pox is very low – but there were other potential complications from some of these diseases, such as deafness. I had measles and mumps simultaneously, and chicken pox immediately afterwards.

I was surprised to learn that 72% of polio cases had no symptoms, up to 5% led to non-paralytic septic meningitis, 0.5% lead to permanent paralysis. Those with temporary paralysis would spend 1-2 weeks in “iron lungs”. The 1916 US outbreak of Covid-19 came to an end on its own, through natural herd immunity, in spite of random public health measures like killing all cats (that is hocus pocus, not science). In 1952, the “experts” sprayed DDT to kill mosquitos, even though mosquitos had nothing to do with the disease. The largest outbreak of polio in the U.S. was in 1952: the CFR was 5.4%. However, the polio virus was transmitted by human fecal matter and was simpler to control than airborne viruses like influenza or SARS-CoV-2. In 1955, an emergency use authorization for the Salk vaccine was issued by the government in just 2 hours.

Compare measles CFR of 2.1% to the U.S. Covid-19 case fatality ratio today – 1.7%. The WHO estimated CFR of influenza is 0.1% +/- (varies by year and location).

I also read about the global influenza pandemic of 1968 that was estimated to have killed (in population adjusted figures scaled to today’s US population) about half as many Americans as Covid-19 may kill. WHO estimated a CFR of up to 0.5%.

I lived through 1968. And I have no memory of business and school closures – no memories of nightly news casts listing the daily body counts. No memories of people wearing face masks. No memories of closed restaurants. (UPDATE mid 2021 – the ’68 death total, if scaled for population, is around 1/3d the total for Covid-19 in 2020/21 so there were different impacts. However, those impacts were not known until the pandemic was over with in ’68, helped along by rapid development of a vaccine.)

How society evaluates relative risk has changed significantly. Today, we see some demanding that schools remain closed until there are zero Covid cases (the so called “ZeroCovid” goal).

Reminder: I am a brain injured idiot who makes observations and asks stupid questions. I do not make predictions.

These comments do not diminish that Covid-19 is a real disease infecting far too many, causing far too many severe cases and hospitalizations, and far too many deaths. Covid-19 is not a hoax.