Saturday, March 14, 2020

Understanding Pandemics

Understanding the numbers is important.  The first to know about is the R - nought (R0) which tells us how contagious it is.  Basically, it indicates how many other people an infected person is likely to infect.  Greater than 1 means the number of infected is likely to grow.

For example, the common Flu is around 1.3, the Coronavirus (COVID-19) based on early data is 1.4 to 3.9, which is likely inflated due to unreported mild cases.  The common Measles is 12-18.

Values of R0 of well-known infectious diseases
Disease Transmission R0
Measles Airborne 12–18
Diphtheria Saliva 6–7
Smallpox Airborne droplet 5–7
Polio Fecal–oral route 5–7
Rubella Airborne droplet 5–7
Mumps Airborne droplet 4–7
Pertussis Airborne droplet 5.5
HIV/AIDS Sexual contact 2–5
SARS Airborne droplet 2–5
COVID-19 (early data) Airborne droplet 1.4–3.9
Influenza Airborne droplet 1.3–3
Ebola Body fluids 1.5–2.5
MERS Airborne droplet 0.3–0.8

Second, is the deaths per 100,000 people.  Because the number of deaths is generally a small, fraction of a percentage, they are measured on a 100,000 scale.

The CDC estimates that so far this season there have been at least 36 million flu illnesses, 370,000 hospitalizations and 22,000 deaths from flu: but possibly as many as 55,000, with a mid point of 38,500.  How does this compare to to the COVID-19?