Naked Science Forum

Life Sciences => Physiology & Medicine => COVID-19 => Topic started by: evan_au on 16/04/2020 22:24:38

Title: Is "Reproduction Number" a useful COVID-19 metric for politicians and public?
Post by: evan_au on 16/04/2020 22:24:38

Day after day the news repeats the mantra "Highest-ever number of new cases/deaths...".
- It is a characteristic of exponential growth that the number of cases accelerates at an accelerating rate.

We have heard the slogan "flatten the curve", and I think the public & politicians understand the concept, but not how their actions affect the outcome.
- Especially when "the curve" is sometimes displayed with a logarithmic vertical scale: any growth is still exponential growth!

I saw the graph below which focuses on the Effective Reproduction Number (R_eff).
- With no special precautions, each COVID-19 patient will infect 2-3 others (R₀)
- If we can keep R_eff down below 1, then fewer and fewer people will catch the disease over time, and we can get it under control
- If there is a new outbreak, R_eff quickly rises above 1, and disease will rapidly grow in the population.

Reproduction_Number_TAS.png (41.46 kB . 321x276 - viewed 2537 times)

Is this a metric that is understandable by politicians and the public?
- Does it convey the idea that we as individuals need to take action to contain spread of the virus?
- Does it offer hints about when it is safe to relax restrictions?
- And when to impose tighter restrictions?

See: https://www.theguardian.com/world/2020/apr/16/coronavirus-the-graphs-that-show-how-australia-is-containing-the-pandemic
https://www.doherty.edu.au/uploads/content_doc/Estimating_changes_in_the_transmission_of_COVID-19_April14-public-release.pdf

Title: Re: Is "Reproduction Number" a useful COVID-19 metric for politicians and public?
Post by: chris on 17/04/2020 14:01:54

UK politicians and journalists are tending to talking about "R nought"; I think I helped a bit with this because I began talking about it early on in the outbreak in simple terms on prominent national networks; I anticipated, correctly as it turned out, that there would be a lot of emphasis on reporting in the coming weeks on maths, stats and modelling. I think people here get the concept.