Saturday, April 18, 2020

R0 Number

 We are reaching our COVID-19 death peak in three days in Connecticut according to a new model by the University of Washington.

Connecticut model

Already people are discussing how we will reopen the state. Our Governor is a decent, cautious man and he wants to make certain he doesn’t open it too soon to let a second wave attack us.

Meet the team advising Gov. Ned Lamont on how to reopen the state after coronavirus infections subside

To understand this pandemic and the reason for social distancing, you must understand the virus’s RO, or reproductive value. The RO represents the number of people someone with the virus will likely infect. If the RO of a virus is 2, each person who gets the disease is expected to transmit it to two others, and those two spread it on to another four, who spread it on to eight, and the number continues to grow exponentially.

The higher the RO number, the more likely the virus is too spread. No one really knows what the RO is of COVID-19, but the World Health organization has estimated it to be between 2 and 2.5

To stop an epidemic, you have to get the RO down to less than one. Social distances, face masks, PPE, all of these things help lower the RO. If you get the RO down to 0.9, the diseas will begin to die off.

But, let's say you get it to 0.9, and then you loosen up the restrictions, it starts roaring back.   1.2 is far worse than 1.1. Even a single 0.1 increase can be the difference in many lives lost and whether or not a health care system gets overwhelmed.

Here is a great video of German Prime Minister Angel Merkel explaining it.

https://youtu.be/22SQVZ4CeXA

In her words, the situation is “thin ice...where caution is the order of the day, not overconfidence.”

The two best way to keep a virus RO below 1 is through herd immunity. That comes either through immunization or through enough people having already been infected that the virus runs out of new people to infect. When you lack herd immunity, all you have left is social distancing.

I hadn’t thought of this before when I desired for the state to be reopened, and in particular, for the swimming pool across the street to open and the schools for my children.

Until we have widespread testing that reveals whether of not we have herd immunity (I believe we are far from it), and or a vaccine (1-2 years away), corona is going to be among us. And while at times it may seem like we have flattened the curve, it can easily come raging back.

Here’s my scary article of the day:

Epidemiologist Delivers Blunt Reality Check On Current Phase Of Coronavirus Pandemic

No Matter How Much You crunch the Numbers This Epidemic is Just Getting Started