The case for herd immunity

Apr 27, 2020
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Let's take a look at our current strategy for fighting Covid 19. We've decided we're going to fight this contagion by "playing it safe." And inso doing, we can only assume that if any given state who has just relaxed its restrictions finds its cases increasing substantially (and who knows what that means, our leaders never bother telling us) then they will go back and clamp down on the current easing and presumably return to the same lockdowns that characterized the first month and a half or so of the outbreak with hopes of keeping the disease spread to a minimum until a vaccine or effective treatment can be developed.

Sounds good, so what's the problem with playing it safe?

1. Economic: You don't need an economist to tell you that by shutting down most of the economy, we're in for an economic crash not seen since, well, it takes us back beyond The Great Depression. Britain's Prime Minister Boris Johnson had to go all the way back to the early part of the 1700s to find a collapse of comparable magnitude. The implications of which are multifold. Livelihoods and dreams in ruins: countless businesses have and will continue to shut down, turning the carefully cultivated futures of literally millions of people to ashes. Long-term unemployment for people living paycheck-to-paycheck resulting in bankruptcies of astounding magnitude, shaking the very foundations of our society.

2. The psychological impact of isolation and loss of income: The Washington Post just ran an article titled (and which requires no further explanation), "The coronavirus pandemic is pushing America into a mental-health crisis. Anxiety and depression are rising. The U.S. is ill-prepared, with some clinics already on the brink of collapse." (https://www.washingtonpost.com/health/2020/05/04/mental-health-coronavirus/)

And people forced to live with each other day in and day out is not a healthy situation. How many domestic violence cases will occur? How many relationships will end? How many irretrievable words will be exchanged between otherwise well-coexisting people? (Personally, if I had to live side-by-side with Jesus Christ for months on end, eventually I'm not so sure one of us wouldn't end up dead.)

3. The unintended death toll: Besides a rise in expected suicides, The International Food Policy Institute just estimated that the economic toll on the world's economy will double the 147 million people living in extreme poverty, likely resulting in millions of deaths through hunger. (https://www.cbsnews.com/news/hunger-crisis-coronavirus-pandemic/)

With all of this in mind the otherwise sound advice of, "Listen to your doctor," by in this case shutting down the economy, makes a physician's words seem myopic. Doctors are not trained to think in these terms. They aren't trained to see the big picture. They see a sick patient and their number one concern is to make them healthy at whatever cost. And our legal system only reinforces this by imposing staggering fines on any doctor that might have forgotten. Unfortunately in all of this it's the Hippocratic Oath itself, "do no harm," that is being forgotten.

So what happens if we "go reckless" and remove restrictions on ourselves and our economies? If instead of trying to keep the pandemic's spread to an absolute minimum, we allow most of us to get the disease? A false argument currently exists that assumes we either shut down everything when under a pandemic's stress or we let 'er rip, best stated by a forestry official's famous quote while Yellowstone Park was in flames during the late 70s: "Burn baby, burn!" Nobody seems to be talking about focusing on better protecting that small percentage of the population that runs a high risk of ending up in a hospital's care while allowing the rest of society to contract the disease, get over it, and get back to work. While estimates vary as to how many people need to be infected and consequently become immune to the disease in order to stop it from spreading, 75% might seem a reasonable assumption. At this point as you may already know, we reach what is referred to as, "herd immunity," when enough people are immune to keep a disease from spreading. But can we even handle an acceleration of infections?

Hospital Supplies

As far as hospital supplies are concerned, it's anybody's guess. We hear about shortages of various hospital supplies, but other than usual anecdotal reports, researching it I was unable to get any idea of exactly what was needed when and where, nor do I doubt anybody can currently answer that question. But I do believe it is not unreasonable to assume that hospital supplies like what one hospital in my state has requested:
  • Unscented hand lotion
  • Simple elastic headbands with buttons for masks
  • Surgical caps with ties and buttons near the ears (NOT the bouffant style)
  • N95 masks
  • Hand sanitizer
  • Non-latex gloves (any size)
  • New digital thermometers
can't be compensated for by either simple improvisation (bullets 1, 2, 3, 5), making do with latex for those not allergic (6) and simply sterilizing what you have (which could apply to many of these.) An N95 mask is nothing other than a basic cloth mask with a small filter fixed to the front that filters out 95 percent of particulate matter in the environment and which under normal conditions can be picked up at the hardware store. Can't these masks be sanitized and the filter strips replaced? I can't believe that in an emergency (like one with the potential for creating a scenario described above) that any of these shortages can't be made up for or accommodated by alternate means. And if they are shortages, by how much and under what conditions? I think this might be taking the adage, "for lack of a nail, a war was lost," a little too far.

This thinking may sound simplistic, but I find myself forced to answer the issue of shortages in such a way since none of these questions seem to be getting adequately addressed by anyone. Other than the usual vague information our media and leaders get away with under normal circumstances, when the issues so profoundly effect our lives more than ever we deserve better, more complete answers to these questions provided to the best of their ability. Instead, we're forced to guess our way around things or trust they have them under control. (And we all know where that can lead us.) And if the people who should know don't know, do we assume these possible shortages can't be dealt with while knowing what's about to hit us through prolonged quarantines?

As for ventilators. it turns out that they were in all probability being over used to begin with resulting in more deaths since ventilation requires sedating the patent, which works to weaken them in other ways. (https://www.statnews.com/2020/04/08/doctors-say-ventilators-overused-for-covid-19/)

Hospital Facilities

Despite what the news media depicts of a nationwide hospital system at the verge of collapse, with the exception of the densest urban area hospitals during the hight of the crisis, the vast majority of our hospitals are currently way under utilized. How do we determine that for our particular state? Since the total number of patients currently hospitalized in every state isn't always available, we can get a pretty good idea by totaling the number of confirmed cases in any state admitted over the last 10 days (being the average time spent in hospital for covid-19 patient) from the list provided here (https://en.wikipedia.org/wiki/Template:COVID-19_pandemic_data/United_States_medical_cases) then dividing that by the average percent hospitalized. Here in New Hampshire it's currently 11% where we are currently treating 107 patients. (https://www.nh.gov/covid19/)

In the meantime like in many states, New Hampshire has set up temporary emergency facilities, which alone totaled 1400 beds. Knowing these beds would be used for covid-19 patients, presumably they are equipped with the necessary facilities to handle these kinds of cases. If only these beds were counted as being usable to treat covid-19 patients, that would still allow for 140 hospital admissions per day (X 10 days average stay = accommodating 1400 patients at a time). But this does not mean the state can only handle 1400 people sick with covid-19 at any given time, it is that many sick who require hospitalization. And what is the true number of infections that represents? Since we know that in New Hampshire 11% of those testing positive for covid-19 are admitted to a hospital, approximately 1300 would have tested positive with 140 of those being admitted.

The current antibody tests can give us an idea of how many people are or have been infected with covid-19. We would probably have more results to compare but the powers that be determined we are better off with no information than some information and so put a stop to quick release of results before extensive peer review takes place. (Like they have all the time in the world and they haven't already used far less complete information to insist we abide by the most draconian resolutions.) The most reported on result (and perhaps the most reliable) being New York State's recent study that found a conservative interpretation of the figure to be 10.7 times the number of confirmed infections to actually be infected. (https://www.foxnews.com/us/new-york-antibody-study-early-results)

Thirteen hundred cases per day testing positive would indicate that about 14,000 had actually been infected (1300 X 10.7). So those 1400 temporary emergency hospital beds represent 140 potential patients testing positive and being admitted per day amongst the 1300 that tested positive, among the 14,000 who were actually infected per day. So if these emergency facilities alone can handle the nursing requirements of 14,000 new total infections in New Hampshire per day, that would therefore accommodate about 420,000 per month (14,000 X 30 days) of the actual total number of infections. The total population of New Hampshire is 1.3 million, meaning under the hypothetical condition that these emergency beds were the only ones available in the state, they could handle 75% saturation of infection amongst the population and allow us to reach herd immunity in as little as 70 days. Of course the infection rate would be in the shape of a curve meaning it would be impossible to calibrate infections to stretch evenly over this time period; however, if we wanted to conclude the pandemic within anything near 70 days--unless you live in a densely packed city that hasn't already been hard-hit--the problem will probably be getting that many people infected that quickly, not keeping them from being infected. If the system appears to be approaching strain, a temporary imposition of shut-downs and increased social distancing can be imposed depending on local conditions.

Get Sick Now, Do It for Grandma

All of those numbers on hospital capabilities assumes the percentage of hospital admissions to actual infections stays the same. But if we were to opt for this quick "in-and-out" approach we could then ask for and provide extraordinary protective measures for the most vulnerable to hospitalization--knowing they would only be subject to its confines and the rest of us to its cost--for a limited period before herd immunity could be achieved amongst the general population. Instead of the battle cry being, "Stay home and keep Grandma from getting sick," it could instead be, "Get sick, do it now, do it for Grandma." In this way, the outbreak could be over and done with before the next flu season comes around (which could begin anytime from October on and which hospitalizes up to .25% of the population) making now the best time to get started before the hospitals start to fill up. A strong argument might be made that this system would actually save lives and save the economy rather than take more lives. Meanwhile the current "safe" drip . . . drip . . . drip method could end up costing more lives in the end than it saves through forcing the most vulnerable to live in a contagious environment for longer periods, through increased suicides and general shortening of lives through hardship, to out-and-out mass starvation amongst the world's very most vulnerable--and claiming these particular lives at a far younger age than could otherwise have been. Couple that with a near guarantee of crippling the world's economy and the "safe" play starts looking like it deserves to be questioned.

While it seems to be part of the human condition to resort to "what ifs" of forecasted eventualities in order to justify playing it safe, allow me to give you one scenario about maintaining our attempt to keep the population "safe" from contracting this virus. What if ten years from now a new strain of coronavirus comes along that is far deadlier than this one and very few have the internal defenses capable of identifying it, and then combatting it? But if ten years from now it comes to pass and we've already had its ilk, those mostly elderly who are the most vulnerable today will in all likelihood have passed on and those who will be amongst the new vulnerable of tomorrow will at least have already had a similar virus. Perhaps it will be dealing with the devil we know today that will keep us alive tomorrow.
 
May 11, 2020
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A brilliantly written summary. Here in NZ it seems robust debate is simply not tolerated. So instead of a balanced approach allowing small business to survive and social mixing to continue, and life to continue, we too have been locked down. The result will be a winter of discontent and all of the horrors you have referred to above. I am 62 and very happy to "let it go". As you have stated, if a truly lethal pandemic hits, the likes of smallpox, the cupboard will be bare.
 
Apr 17, 2020
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I found the best source for state-by-state information is at:


(Reliable? I don't know... but I think it's what JHU uses)

Unfortunately, not all states report all information, so that makes things a little bit difficult.

For New Hampshire:


You can calculate the active cases by taking the positive number of cases and subtracting recovered and subtracting deaths. For New Hampshire (at the time of this post) the active cases were 1798 and the number actively hospitalized is 113 or 6.2% of all the active cases in New Hampshire.

If you actually take a look at all of the data - but you can only include states that report recovered cases, otherwise your number of active cases is going to be substantially wrong. The average hospitalization rate in the US (for states that report hospitalizations) is 4.5% with states averaging 780 active hospitalizations - that seems a little high.

Remove New York and New Jersey from this model and your average active number of hospitalizations goes down to 472 - which might be a little high, but reasonable. But this makes your average hospitalization rate 7.1% but still probably reasonable. This would seem to indicate that New Hampshire is in a decent enough spot in this pandemic not to be too fearful.

Probably a better telling stat would be, just how much hospital capacity does New Hampshire have? I'm assuming the state has more than 113 hospital beds, so those 113 Covid-19 patients aren't consuming all of their hospital capacity. Additionally knowing how many ICU cases are in New Hampshire (they don't report that) and the overall ICU capacity for New Hampshire might be an even better stat.

And as you say, the hospitalizations are more than likely in large urban areas. New York state has 7,226 hospitalizations and 257,052 active cases. How much of those are in Upstate New York and how many are in the New York City area? I'd say a large portion of those are in NYC - but I'm just guessing. But it also underscores where all of this divided up information could be more beneficial if we were able to look at it in terms of US Congressional Districts - which I believe would show that the more rural areas are hardly affected by any of this.
 

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