Comparisons between Covid-19 and similar

Last data refresh: Thu, 09 Jul 2020 14:56:42 GMT. China: 2020-07-09 22:56
India: 2020-07-09 20:26
S Africa: 2020-07-09 16:56
UK: 2020-07-09 15:56
New York: 2020-07-09 10:56
LA: 2020-07-09 07:56

The figures in the next two tables come from different sources and are slightly out of synch with each other.

Comparisons of Case Fatality Rates

DiseaseCase Fatality Rate
Rabies~ 99%
Ebola83 - 90%
Plague, bubonic5 - 60%
Plague, pneumonic50%
Middle Eastern Respiratory Syndrome (MERS) 45%
Plague, septicemic30 - 50%
Novel coronavirus (SARS-Cov-2)7.48%
Severe acute respiratory syndrome (SARS)11%
Spanish (1918) flu> 2.5%

Comparisons of Recent Similar Coronaviruses

DiseaseYearCasesDeaths
Novel coronavirus (SARS-Cov-2)2019 - present12,153,569551,154
Severe acute respiratory syndrome (SARS)2002 - 20038,098774
Middle East respiratory syndrome-related coronavirus (MERS-CoV)2012 - 2015>2,000>600
H5N92013 - 20171,622619
H5N12003 - 2014701407


R0, the Basic Reproductive Number

R0 is a measure of how many other people each patient infects. For example, with an R0 of 10, each person that catches the disease will infect 10 others (on average).
For example:

GenerationNew people infected
11
210
3100
41000

As you can see, the numbers can ramp up very quickly.

The latest estimates for R0 for Covid-19 are between 4.7 and 6.6, and possibly up to as high as 11.3.

R0 Comparisons of Similar Coronaviruses

DiseaseR0Notes
Novel coronavirus (SARS-Cov-2)4.7 — 6.6
CI: 2.8 — 11.3
Source (11 February 2020)
Novel coronavirus (SARS-Cov-2)2.2
(95% CI, 1.4 — 3.9)
Source (29 January 2020)
Novel coronavirus (SARS-Cov-2)2.2
(90% HDI: 1.4 — 3.8)
Source (24 January 2020)
Severe acute respiratory syndrome (SARS)2 — 5Airborne droplet
Spanish (1918) flu2 — 3Airborne droplet
Middle East respiratory syndrome-related coronavirus (MERS-CoV)0.3 — 0.8Airborne droplet


The effect of different R0 values

The following graph shows the effect of different values of R0, namely 1.5, 2, 3, 4, 5, 6.

Each line stops at the generation at which it is still below world population, which is just under 8 billion people.
The line for R0=1.5 does not get high enough to be visible, given the Y-axis scale, and the limit of 33 generations.

The real question is "how long is one generation?" There are estimates that people become infective within 12 to 24 hours of becoming being infected. This puts the length of one generation at 1 day, but this does not appear to be correct, unless the drastic lockdowns in China are distorting the R0 figures. Also, as more people become infected, the available population in a given area able to be infected drops off dramatically, slowing the R0.

So the chart below assumes "everyone in the world all together in one room, and people moving around constantly so that those who are infected can find new people to infect," which is not how the world actually is.

So view the chart as showing "worst possible case" of spread potential.



For different R0, which generation exceeds world population

R0Generation > world population
234
322
418
516
614
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