- Joined
- Mar 6, 2019
- Messages
- 20,970
- Reaction score
- 16,595
- Location
- PNW
- Gender
- Male
- Political Leaning
- Other
As schools reopen, and people get complacent about the COVID in our midst, it seems appropriate to address some conceptions and misconceptions that are, like the virus, spreading throughout the population. There have been numerous reports about "superspreader" events, various "clusters" at colleges, in towns, and from events, and the summer "surge" we've gone through and another expected in the fall - and worse, its conjunction with the seasonal flu. Overall, we're looking at this the wrong way. I'll get back to that in a moment.
In other threads, discussions and articles, the concept of R0 - or "R Naught" has been discussed, what it is and what it isn't. R0 is the measure of how transmissible a disease is in the population. An R0 over 1 is expanding in a population. Under 1 is declining - that is, spreading slower - and will eventually peter out. The R0 for COVID-19 has been estimated at between 1.4 and 4, with 2.5 being the "mean value". In comparison, annual flu is typically between 1.2 and 1.4, whereas Measles is somewhere between 12 and 18 - extremely contagious.
R0 represents the ‘natural’ infectiousness of a new bug, the effective reproductive number (sometimes written as R[sub]e[/sub] or simply as R) tells us how many new cases are likely to be caused by each existing case. That is, how many people will catch the virus now, given that some people might be immune and/or social distancing measures are in place. Understanding the relationship between R0 and R[sub]e[/sub] is vitally important to understanding the spread of COVID-19, and understanding clusters, superspreaders and surges.
R0 represents an average. In a group of 10 contagious people, many will not spread the disease at all [especially if they and the people they contact take precautions]. To make up for that lack of spread - and because we're talking about an average here, that means the others will infect more than 2.5 people. A "cluster" is a group of infections that are traced to a particular source. For example: "COVID-19 cluster in Mass. traced back to bachelorette party in R.I." In a group of 20 attendees, 19 got COVID. (That makes up for the 8 who got nothing.) That is called a "cluster". If one person or event is responsible for a large number of cases, that is referred to, colloquially, as a "superspreader" event/person. (That is not a "medical" term.) When a number of clusters converge in a population, that is referred to as a "surge" or "outbreak".
Now, getting back to what I skipped: Masks, social distancing and hygiene reduce the R[sub]e[/sub]. That is how Two Missouri hairstylists with coronavirus saw 140 clients in their salon, but no one got infected (BI). The EU and Asia have managed their R[sub]e[/sub] to below 1 and have reduced their outbreaks to a manageable level. (We, in contrast, have not.)
Sturgis represents an event where, unlike those stylists, virtually no one was adhering to common sense practices to reduce the risk of spread. As a result, there are 8 "clusters" that have been traced to the event, and spread to 8 States. That is an "outbreak" which will likely lead to a "surge", as adequate contact tracing is virtually impossible. But outbreaks and surges are anticipated in any epidemic. The disease does not pass equally throughout the population, it waxes and wanes, and gets distributed unevenly. What can be done is to slow it down by...
Wearing a mask, keeping your distance while possible, and washing your hands frequently. Get the R[sub]e[/sub] below 1 and we will be successful - like most of the developed world.
In other threads, discussions and articles, the concept of R0 - or "R Naught" has been discussed, what it is and what it isn't. R0 is the measure of how transmissible a disease is in the population. An R0 over 1 is expanding in a population. Under 1 is declining - that is, spreading slower - and will eventually peter out. The R0 for COVID-19 has been estimated at between 1.4 and 4, with 2.5 being the "mean value". In comparison, annual flu is typically between 1.2 and 1.4, whereas Measles is somewhere between 12 and 18 - extremely contagious.
R0 represents the ‘natural’ infectiousness of a new bug, the effective reproductive number (sometimes written as R[sub]e[/sub] or simply as R) tells us how many new cases are likely to be caused by each existing case. That is, how many people will catch the virus now, given that some people might be immune and/or social distancing measures are in place. Understanding the relationship between R0 and R[sub]e[/sub] is vitally important to understanding the spread of COVID-19, and understanding clusters, superspreaders and surges.
R0 represents an average. In a group of 10 contagious people, many will not spread the disease at all [especially if they and the people they contact take precautions]. To make up for that lack of spread - and because we're talking about an average here, that means the others will infect more than 2.5 people. A "cluster" is a group of infections that are traced to a particular source. For example: "COVID-19 cluster in Mass. traced back to bachelorette party in R.I." In a group of 20 attendees, 19 got COVID. (That makes up for the 8 who got nothing.) That is called a "cluster". If one person or event is responsible for a large number of cases, that is referred to, colloquially, as a "superspreader" event/person. (That is not a "medical" term.) When a number of clusters converge in a population, that is referred to as a "surge" or "outbreak".
Now, getting back to what I skipped: Masks, social distancing and hygiene reduce the R[sub]e[/sub]. That is how Two Missouri hairstylists with coronavirus saw 140 clients in their salon, but no one got infected (BI). The EU and Asia have managed their R[sub]e[/sub] to below 1 and have reduced their outbreaks to a manageable level. (We, in contrast, have not.)
Sturgis represents an event where, unlike those stylists, virtually no one was adhering to common sense practices to reduce the risk of spread. As a result, there are 8 "clusters" that have been traced to the event, and spread to 8 States. That is an "outbreak" which will likely lead to a "surge", as adequate contact tracing is virtually impossible. But outbreaks and surges are anticipated in any epidemic. The disease does not pass equally throughout the population, it waxes and wanes, and gets distributed unevenly. What can be done is to slow it down by...
Wearing a mask, keeping your distance while possible, and washing your hands frequently. Get the R[sub]e[/sub] below 1 and we will be successful - like most of the developed world.
Last edited: