Active pool... and your odds
Why is "Active" a key measure?

Active is, analogously speaking, the pool of fuel for the virus's continuation. It is the number of people actively contagious and the source of new infections. The larger the pool the more subsequent infection. New cases are contastantly entering this pool and others recover and are no longer contagious so they leave the pool.

The odds of infection determine the the overall number of new cases. Who of that number, is matter of luck. The greater the odds though the less chance you have of avoiding it, in this case, "bad", luck. Some factors of the odds you can lower for yourself by social distancing. Other factors are determined by the virus itself, and still other factors are controlled by the community and the other person. And vice versa in this, your behavior affects the odds of bad luck to others.

In simplistic terms, the odds come down to the following factors:

  1. odds of an uninfected person coming in contact with an infected person. The more infected people out and about, the higher the odds in this factor. You can lower your personal odds here by the social distancing measure of limiting your number of contacts.

  2. times

  3. the odds of the infection reaching the uninfected person if there is a contact. This factor can be directly lowered by social distancing measures taken by both individuals in individual encounters, i.e. masks and distance.

  4. times

  5. And the final factor: contagiousness of the virus combined with your suspectibility. This is by and large determined by the virus itself and the human body. As we all know this virus is extremely contagious. I don't know how many would get it if in contact, but sure seems to me like the virus bats more than 700 and not letting up.

When we "slow the spread" by social distancing, we lower the flow going into the pool. Eventually it gets to a steady state: new infections in are about equal to previous people coming out. As can be seen in the graph of the active pool over time, we, as a country, did achieve steady state and then some early on during lockdowns, and later at the beginning of the vaccinations when they were really effective for the original strain and stopped the infection. The pool size was going down. Don't think this was by accident. We did really well in the lockdowns and right after, but then summer hit and many relaxed I think. After another round of intense targeted efforts, we had it back to the pool slowly going down gain. And then we had the vaccine. Sadly, it is making a turn up again with the delta variant making its rounds.
Generally speaking the rate of change will remain the same as long as the infectivity of the irus reamins about the same and our social distancing remains about the same level. Not sure what is causing it go back up now, suspect a combination of both. Some maybe be due to lots of chlidren going back to school for first time since beggining, and/or more people tired of wearing masks and who are defying that ask and maybe just defying fate.

The virus though is not over and still widespread, extremely infectious and excessively deadly to over half of our population, and extremely deadly to the elderly.

Some experts estimate that when masks are used on both sides it could lower the odds of transmission in an encounter (2nd part above) by as much as 60% to 70%. No, not 100% but certainly nothing to sneeze at ;)

Masks... Are they Effective? 6 Top ↩
Masks... Effective?

Wearing a mask - Ugh! Right?


Yes, but I think they have been effective.

After seeing over the summer, the various phases of behaviors: at first most strictly adhering to social distancing, then when summer came, many relaxing then, about Mid July, trouble so targetted re-attention. The active pool of infection numbers followed: went way down, then up, then down again. So, I am convinced and cannot stress enough the importance of social distancing in keeping the infection rate down.

In this, am only adding to the voices of our Surgeon General, VADM Jerome M. Adams, and Dr Redfield of the CDC, and other health officials:

Wear a mask when cannot maintain physical distance.


Although there is much variability depending on the type of mask and its use. For example N95's are better than a 90-95% block to incoming. As for cloth masks, while they do block some incoming, they are not in that league.

What we need in this case though, more, are blocks on the outgoing side for situation where a person has the infection and doesn't know it. Turns out that asymptomatic people have been, and still are, the main source of spread.

From various studies, it looks like cloth masks could be pretty good for the outgoing side, i.e. blocking larger droplets that may carry the virus and limiting much of the rest to traveling only very short distance. Can maybe argue about how much, but commonsense, any barrier is better than none and will lower the odds of infection.

Why wear masks for Covid-19 - Mayo Clinic "Still confused...? Science behind how...prevents" - Univ of CA-SF See it live - Livescience


Masks seem like a pretty simple idea to understand, are fairly effective. No doubt inconvenient and annoying but it is a minimal and rare ask. And does not seem like an unreasonable ask or precaution given the amount of death in the situation at the moment. Normally we know who is sick and could quarantine or limit mask wearing to those who are infectious, but for this virus that does not work. Not only is it super contagious, but most of the infection spread is invisible, i.e. by those who do not even know they have it. So I think that is why we are all asked to wear a mask, in case it is we who become asymptomatically infectious.

The numbers reflect that it has been worth the effort that everyone is making, especially in "hot" zones.

So please stay the course. It is short term inconvenience versus possibility of permanent death for you or someone else you may spread the infection to if you should get it. Hopefully though we collectively keep the spread down and most of us will not get it.

The vaccine hopefully/thankfully is around the corner.

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Sturgis Bike Rally

BTW Don't think masks and social distancing matter?
Before and after Sturgis Bike Rally.

          Sturgis Bike Rally in South Dakota Aug 7 - Aug 16 2020              
Surrounding Counties Population Days Since max % from max Sprd Rate Accel Hot: contag /100 Dths Category Active 7d Case+ 1 wk prior Category Actv -1 Incr -1 2 wk prior Category Actv -2 Incr -2 Risk
Prior to 8/3/2020 7/27/20 7/20/20  
Meade 28,332 30 -77% 4.1% -25% 0.18 0 9 <=10 126 9 7 watch 83 9 9 <=10 52 4 Very Low
Lawrence 25,844 108 -66% 15.5% 8% 0.17 0 9 <=10 74 6 9 <=10 65 3 9 <=10 43 3 Very Low
Pennington 113,775 11 -11% 7.7% 7% 0.62 8 8 down 548 59 9 <=10 668 61 5 spread 711 84 Very Low
   
During 8/24/2020 8/17/20 8/10/20  
Meade 0 0% 16.4% 212% 1.23 0 7 watch 349 64 9 <=10 163 12 9 <=10 165 18 Very Low -> watch
Lawrence 0 0% 11.4% 112% 1.26 1 7 watch 326 46 9 <=10 259 14 7 watch 206 28 Very Low -> watch
Pennington 0 0% 11.8% 77% 0.67 4 3 Hi Sprd 762 119 9 <=10 512 55 9 <=10 532 51 Very Low -> High
   
After Rally 914/20 9/7/20 8/31/20  
Meade 28,332 11 -65% 6.2% 70% 1.56 2 8 down 441 47 9 <=10 796 45 6 decel 863 130 Moderate -> Low
Lawrence 25,844 16 -70% 5.2% 43% 1.34 3 8 down 346 27 9 <=10 646 38 5 spread 698 105 Moderate -> Low
Pennington 113,775 11 -59% 5.7% 8% 1.42 0 8 down 1615 179 8 down 2359 203 3 Hi Sprd 2016 362 High -> Low
Social distancing in this area may be pretty effective, because risk was very low
to begin with and looks like people were aware and may have stepped up to bring down
an increased spread. Rate was slowed quickly after the rally and Acceleration is coming down.
      Prior After           After Rally
  7/20/20 7/27/20 8/3/20 8/10/20 8/17/20 8/24/20 8/31/20 9/7/20 9/14/20 Active+ Cases
SprdRate 9.1% 8.9% 8.3% 11.5% 5.8% 13.2% 13.1% 4.2% 5.7%
Accel -3% 50% 3% 36% -42% 134% 3% -68% 40%
Active 806 816 748 903 934 1437 3577 3801 2402 1596
Cases/wk 91 73 74 97 81 229 597 286 253 1543
 
Avg cases/wk before 79.33  
Avg during and after 257.17
Nominal cases using avg prior to rally minus 476
Estimate of cases from rally: after rally - what would have been using prior avg 1067

From what I saw not much effort at mask wearing nor social distancing... Fomrt he numbers above it definitely looked like a significant rise in infections, so it mattered.

Franky was disappointed to see people not social distancing. I admire those who do not let fear stop them from living. But, it's not like one cannot be both brave and smart, is it?

So even if you may not be that vulnerable and are ok taking the risk yourself, and even if the people around you are too, unless you can contain the virus to that group, your risk is our risk. Many smart determined people have tried to contain the virus, but have yet to do it successfully. The best we have is slowing the spread until we can get a vaccine.

Note, if you want/insist on taking the risk yourself, maybe quarantine yourself immediately after taking the risk. Testing out of quarantine may be an option. Note that it may take 2 to 5 days for it to show in a test and during that you are contagious if you have it, so take that into account when planning oyur quarantine. See the CDC site for more detailed guidance on quarantining whne you hav ehad possible exposure.

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Herd Immunuity

Thought on how to use it, not abuse it


Although we have slowed the spread in the past, slowing will not continue on its own until we reach a point where the odds of infection are low enough to keep the active pool going down without our help. Herd immunity directly affects the first factor in the odds, namely the number of contacts between an infected person and suspectible person. As more of the population gets this virus and presumably becomes immune, less percentage of contacts are suspectible. This directly lowers one of the subfactors in the odds and thus less spread on average from those infected -- assuming all else equal.

I believe the experts when they say we would need at least 60 to 70% of the population immune for this to go down on its own and it looks to me like we are far from that. Dr Redfield in a congressional panel in early September, I think mentioned in passing his earlier estimate of about 10% immunity overall.

Using the constants and numbers in the model here, as of late September (Sept 23, 2020), the estimate here is little under 15% of the US population has gotten this virus. As of Nov 20th, about 20%. For purposes of modelling here, it is assumed people remain immune for at least the intermediate foreseeable future.

The % of population immunity affects the odds of infection. So if the odds were generally "X" without herd immunity, the odds would lower to about (1-immunity%) of X, eg. if 15% immunity in an area, the odds of infection would be lowered approximately to 85% of X, all else being equal. The immunity % varies widely within the nation as can be seen at in the links to the CDC serological studies, CDC Seroprevalence Survey.

Herd immunity is great, but what might be helpful to understand, is that if we simultaneously relax vigilance and social distancing as things look like they are getting better, that 20%, or whatever %, is quickly nullified! There is no question in my mind that nullification was and is happening. Big culprits: summer parties and gatherings without social distancing or masks; widespread protests with packed people, albeit most observing mask wearing during the summer; then as campaigns ramped up nullification accelerated where there was, on top of close quarters in the crowds, little to no masking wearing; and finally new protests on lockdowns where, the same "caution to the wind", specfically no mask wearing, may be being done defiantly/purposefully (?, but I think may be misguidely) as part of the protest "message". The lockdown protests imo are not necessarily misguided but the "caution to the wind" may be. Again, just my opinion.

OK, well how can we use herd immunity then? Please see the projection tracks.

Each track assumes that all the subfactors that make up the odds of infection, like social distancing and number of contacts on average per day, remain the same over time, other than the % herd immunity. We are at a level of herd immunity where it looks like the curve bends pretty well assuming we keep up efforts measured at the start of the track. The tracks though are ratcheting up rather than down as they were in May, and in October, ratched up a lot.

Imagine though if we would/could keep social distancing vigilance up and maybe even ratchet down the tracks again as we had earlier. This could result in many less cases and death in the medium term than the course we are on (as of November).

If we did this, we'd be using herd immunity - instead abusing it. My use of the word "abusing" is a bit dramatic to get attention and of some literary license. By it I mean, our (not all but enough of us) seeing and using the slowing of spread as a signal or allowance to stop doing our part in social distancing. May looks like things are now doing fine and not needed anymore, or, some may see things are not "so" bad, that can stop doing what don't want to do, which is wear a mask etc. However, I think we all know it would be better if we did. Yet, there seems to have been significant relaxing at every chance/turn, when when things look better. Not by everyone, but by substantial numbers of people. That has then nullified the herd immunity's effect and our prior work at social distancing and we go right back into untenable spread and deaths. This nulllification is what I mean by abusing it.

Unfortunately "non-mask wearing" has become more important, or perhaps fashionable, for some to do as a political badge/statement, over it's use as a commonsense health community-level precaution within a pandemic. I do not want to offend anyone and don't know for sure, but when put that way, on its face that prioritizing of a fashion/political statement sounds kind of ridiculous to me, especially considering the "in a pandemic" part.

Regardless, I know and will defend people making their own choices in life, but also know it is easy to get carried away in a wave of political fervor or in response to frustration, even to the point of losing perspective of the situation and reality. It might be good to be careful and not to get too carried away though, especially when the reality is life and death. Also, because I do think many doing this, are in real life, responsible family members and parents who have parents, and in many cases are rock and pillars in their communities, I would urge a re-think of that non-mask wearing, "caution to the wind", part.... at least until the people being put in danger can protect themselves from your choices...

After seeing all the youth out there, seemingly trying to get this during the summer and early Fall, and now this defiance based on the false rationalization comments that "social distancing and masks and the lockdowns did not work" (cannot buy this rationalization though - Looks to me like these measures are not working where people are defying them!), I wonder if people are trying to hasten the attainment of herd immunity just to get through this quicker. Have heard some public figures postulate and question whether we would be better off if we'd have followed this path, or follow it now. Really? Are we close?

As to the close - not really as stated above. As to Really?...

In a detached theoretical sense, maybe this may seem a plausible path to consider. I would urge, in accord with the age old adage, to "think before act" though. This is life and death here.

The argument for it goes: for those who have little risk it might be better choice to take the risk so to live lives, keep up with learning as falling behind might be permanent loss, and make a living to keep themselves and their families going. Also need to consider that we need to keep the country functioning above all else. All things in life are risk tradeoffs and those for sure are valid ones. The problem comes though when people take the message and make it all or nothing, full go in one direction or the other. So before going off and throwing ALL caution to the wind, as I see many doing, please think about whether you really need to it that way, versus a way where you still take precautions where you can. And please do not let the hypocrisy of others, nor the over the top draconism of some of the rules being levied by some leaders, take over your focus such that you lose sight of the reality of the situation to the detriment of your own thinking and choices, no matter how infuriating that hypocrisy may be!

The unmoving, glaring reality at the moment, even if some try to deflect focus elsewhere, is that this virus is not going away and no one is in a bubble. Even those trying their darnest to be in one cannot achieve this. So today, the infection you get will most assuredly get to others before you know you even have it, and then to those who are at risk. Many will die and are dying. The vulnerable, and people who do not choose to be at risk, are not yet able to protect themselves, by themselves. Hopefully this will change soon with widely available vaccine, but we are not there yet... So it is worth it, and imo, morally and practically called for, that all of us, as members of communities, socially distance and wear masks when out and around others as much as is practical... until that time.

And for those advocating not worrying as much and just go for herd immunuty, by arguing "why bother when everyone is going to get this eventually". The fundamental flaw in logic there, is that not everyone will get this if we get a vaccine. And that is imminent. And if a lot of people try this, please let me remind you, the natural course of the virus has not changed. We have only artifically reduced the infectivity by our social distancing. So the 1M to 1.5M deaths scenario we were facing in March, before we succesfully slowed the spread, is still there waiting for our guards to come down.

In conclusion,

From the graphs, it can be seen we were holding our own with the combined efforts in social distancing and jumping on outbreaks as they occur. With a vaccine likely soon, a better course may be to get back on that course, stay the course for the next few months with as much social distancing as is practical and use herd immunity to help us keep deaths to a minimum. When the vaccine is available, first use it to protect the vulnerable and lower the death count drastically, and then get ourselves to herd immunity and virus eradication as fast as possible.

.... Just an idea.

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