# How Virulent is COVID-19?

Here’s the summary my personal research into the science of COVID-19.

This is so I can educate myself, friends and family and help debunk the proliferation of unscientific nonsense.

So let’s get a bit techie and look at the numbers!

**Definitions**

**R0 (R Nought)** is the “**Basic Reproduction Ratio**” of a pathogen. The expected number of cases **directly generated** by one case in a population where all (non-infected or immunized) individuals are susceptible to infection.

https://en.m.wikipedia.org/wiki/Basic_reproduction_number

**R0 > 1**: Pathogen spread grows**R0 = 1**: Pathogen spread stable**R0 < 1**: Pathogen spread reduces (dies out)

*The larger the R0, the faster the reproduction rate. *

#### Example: R0 = 2

- 2 people will each infect 2 others
- Let this happen just 5 times
- Infected = 2x2x2x2x2 = 32

**Incubation** **Period: **The time from infection to illness.

**Serial Interval (SI)**: Time taken for **one R0 cycle**. The mean period between symptom onset in an infector and an infectee.

The serial interval of COVID-19 is close to or shorter than its median incubation period. This suggests that a substantial proportion of secondary transmission may occur prior to illness onset. -PubMed-

**Transmission**: All the following pathogens are transmitted via** airborne droplets**.

**R0 – Viral Comparisons**

#### The Scary Numbers

The following should show you why COVID-19 is WAY more virulent (severe or harmful) than the ‘Flu. and just a bit less virulent then the 1348 Bubonic Plague!

**Black Death – 1348 (Yersinia pestis)**

**R0: 3**(2.8-3.5)- 10 cycles = 59,000
- 15 cycles = 14 million
- 20 cycles = 3.5 billion

**Mean SI:: 4**(2-7) days- World Population (1348): 475 million
- Infected: 150+ million (30%+)
- Killed: 50 million (10%)
- Targeted: Everyone!

*~ 120 days (30 x 4) to potentially infect half the world!*

They had **NO idea what caused it **(miasma) or any treatments to slow the spread and deaths.

**Spanish Flu – 1918 (H1N1)**

**R0: 2.0**(1.4-2.8)- 10 cycles = 1024
- 15 cycles = 32,768
- 20 cycles = 1 million
- 25 cycles = 34 million
- 30 cycles = 1 billion

**Mean SI:: 4**(2-7) days- World Population (1919): 2 billion
- Infected: 500 million (25%)
- Killed: 100 million (5%)
- Targeted: 20-40y/o

*~ 120 days (30 x 4) to potentially infect half the world!*

They had **NO idea where it came from **or any treatments other than isolation.

**Viral Influenza – Seasonal Flu (A,B,C,D)**

**R0: 1.3**(0.9-2.1)- 10 cycles = 14
- 15 cycles = 51
- 20 cycles = 190
- 25 cycles = 705
- 30 cycles = 2,620
- 60 cycles = 6.8 billion

**Mean SI: 2**(1-4) days- World Population (2019): ~8 billion
- Annual Infected: ~500 million
- Annual Serious: ~5 million
- Annual Deaths: ~500,000
- Targets: Young, Old, Pregnant, Compromised

** ~ 120 days (60 x 2**)

*to potentially infect an unprotected world.*But we now have **treatments**, **vaccines** AND **isolation** to slow the spread and deaths.

**COVID-19 (SARS-CoV-2)**

**R0: 2.5**(1.4 – 3.9)- 10 cycles = 9537
- 15 cycles = 931,000
- 20 cycles = 91 million
- 25 cycles = 8.88 billion

**Mean SI:**5.5 (3-14) days (WHO)- World Population (2019): ~8 billion
- Infected: ~1 million (so far)
- Killed: ~100,000 (so far)
- Targets: Everyone! (Especially Health Compromised)

*This means COVID-19 could take only 137 days (25 x 5.5 ) to potentially infect a completely unprotected world!*

**We currently have NO treatments and vaccines (only isolation and distancing) to slow the spread and deaths.**