Herd Immunity through Managed Exposure

What types of animals are in herds? - QuoraThis is a proposal to deliberately infect and quarantine the lowest-risk population on a voluntary basis to achieve herd immunity over a 6-12 month period to minimize deaths and economic impact.

What is the end game to the COVID-19 pandemic?

The only ways out of the current COVID-19 pandemic are:

1.  Completely destroy the virus – which means get to a point where nobody is a carrier of the virus.

2.  Acquire herd immunity  (whether through living through the disease or through vaccination)

I am going to assume that option #1 is impossible at this point, although if there are ideas, I think there would be a very high interest by many people.

This proposal is focused on acquiring herd immunity.  Here are some interesting articles on herd immunity for those interested:

Wikipedia, Technology Review, American Heart Association, New York Times article regarding Corona-virus immunity

The papers that are circulating is calculating the COVID-19 basic reproduction number (R0) to be about 3.   Some papers estimated a slight lower number.  You can think about this as the average number of new infections caused by each case.    At this rate, the herd immunity % we need to get to is around 2/3 of the population (66%).   Although, there are herd immunity threshold numbers below 50% that are circulating.

The questions we are wrestling with are:

1. How do we do it?

2. How long will it take?

3. How many people will die?

4. What is the economic impact?

Currently, the most optimistic estimates (by WHO) for how long it will take to develop and distribute a vaccine is about 18 months.  Normally it takes between 2-5 years to develop.  https://www.sciencealert.com/who-says-a-coronavirus-vaccine-is-18-months-away

So, we can assume that developing herd immunity through a vaccine will take at least 18 months (likely longer). 

Most reports ignore the economic costs of the current social distancing policies, but these struggles are real.  In the U.S., we are in month 1 and Congress just allocated trillions of dollars to offset the stay-at-home mandates and guidelines.  This will provide a couple thousand dollars in benefits to families which may help pay for rent, bills, and food for a few months at most, but most Americans do not have 18 months of emergency savings.  The median savings account is around $5,000.  https://www.fool.com/retirement/2018/09/24/heres-how-much-the-average-american-household-has.aspx  This means that for more than half of Americans, they can last about 3 months at most with their savings if they do not work.  If the unemployment rate continues every week, states will either have to severely modify their unemployment benefits or run out of cash very quickly.   First time unemployment claims reached 3.3M according to the Department of Labor on March 26th.  The previous week claims were around 280,000, so it saw an increase by more than 10x just within a few weeks.

Most of the discussion and debate around COVID-19 has been around how we save lives – which is appropriate.  However, in many people’s minds, there is a looming concern about the economic burden that our current mitigation strategies are placing on families.  These concerns include joblessness, homelessness, and hunger.

I have not yet heard a political leader come out and say directly what the end game is to our current social distancing strategy.  The answer is not one that really any of us want to hear.  This graph shows it best from the Imperial College COVID-19 Response Team:

image

If we go into a mode of heavy social distancing (suppression), we can keep the virus from spreading.  However, when we come out of the suppression, the virus infections will flare up again, and to prevent the rapid infection, we have to go into social distancing mode again. 

The assumption then, is that we will continue these suppression interventions (social distancing mandates) on and off for at least the next 18 months until a vaccine is found.  OR until about 66% of our population gets randomly infected.  In the meanwhile, we will try our best to shield the vulnerable population.  This conclusion is rarely talked about (likely because it is very bad news), but an alternative end game has not been explicitly proposed.  This is indeed the conclusion of the Imperial College report, with an admission that economic impacts are not considered at all in their report:

We do not consider the wider social and economic costs of suppression, which will be high and may be disproportionately so in lower income settings. Moreover,suppression strategies will need to be maintained in some manner until vaccines or effective treatments become available to avoid the risk of later epidemics. Our analysis highlights the challenging decisions faced by all governments in the coming weeks and months, but demonstrates the extent to which rapid, decisive and collective action now could save millions of lives.

Here is a medium article discussing this problem. 

An Alternative Proposal:  Managed Exposure

Create a managed exposure program to infect the lowest risk population over the next 6-12 months.   Others are starting to seriously consider this proposal.  Here is a medium article making this proposal.

Here is the hospitalization, ICU, and fatality rates by age group according to the CDC.

image

If we just looked at King County (Seattle area), we have a population of around 2.2M according to the U.S. Census.    To infect 66% of the population, we would be looking at around 1.4M people.  If we assume that the age demographic of King County is similar to that of the U.S., approximately 66% of the population is under the age of 45.   If we let the virus spread randomly (with no controls), we can expect the following fatality rate until we reach herd immunity:
image

If we deliberately infect the younger population through a volunteer program, we can  reduce the fatality rate by over 85%.  I am making assumptions that most healthy 20-44 year olds will volunteer for the sake of the vulnerable population.  There would likely be a set of parents that are very concerned for their children.  However, if it meant being able to send their children back to school and return to normal life, hopefully many parents would consider it similar to the chicken pox. It is possible we would need to recruit healthy 45-54 year olds, even thought their fatality rate is 4.5X that of the 20-44 group.

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Possible Logistics

Here is a possible proposal of how the program could work.  The plan assumes a war-time mentality where considerable resources would be diverted to the effort.  All citizens in the volunteer age groups would be asked to prepare physically and try to get in good health through exercise and diet.

1.  We would screen volunteers to deliberately become infected by the Corona Virus.  Volunteers should be healthy and under the age of 45.  Families can volunteer together if everyone is under 45.  Depending on the number of volunteers, we may consider opening it up to the 45-54 year old age group if they are in great health.

2. Qualified individuals and families would be infected with the virus and they should self-quarantine at home.  For those that might be living with roommates/family/relatives in the vulnerable population, they should quarantine themselves in a managed hotel/motel facility.  This could be funded partially by the volunteer, the municipality (city/county/state), and the vendor (hotel/motel).   There are about 14,000 hotel/motel rooms in King County.   Similarly, restaurants could be enlisted to provide food regularly to the centers where the funding model would be similar.

3.  Quarantine administrators would oversee the quarantine centers as well as those that are quarantining at home.  They would virtually see each patient regularly to triage if they need hospitalization or special equipment.    Those that are out of work and have developed immunity could be trained specifically to become a corona-virus quarantine administrator.  They would be asked to do as much as practical and safe before involving trained nurses/doctors to conserve our medical resources for those that absolutely need it. They would also administer 2 tests to ensure the volunteers are clear of the virus before volunteers are allowed out.

  • PCR test to see if the volunteer actively is a carrier of the viral genetic material.  They should stay in quarantine until they receive a negative result.
  • Serological Test that test for antibodies.  This should be positive, before leaving the quarantine.

4.  Individuals that have successfully been exposed and have developed anti-bodies would receive a pin, hat, or ring (or some other public indicator) that indicates that they have gone through the process and are immune.  These individuals are free to continue their lives normally.  They can work, they can go to restaurants, to the gym, on vacations, etc.    In the beginning, there will likely be a high demand for immune individuals that can work.    Restaurants, hotels, retail outlets, and designated business would check clients to make sure they are immune.  Those that try to falsely claim immunity without having been infected should receive criminal penalties.

5.  The vulnerable population should be in strict lockdown until we have reached herd immunity.  They should only be served by the immune population.

Rollout of program

  1. Survey the population.  See how many would be interested in participating in a voluntary managed exposure program.
  2. Determine the best way to “safely” expose volunteers.  Create a schedule for exposure so that the number of those that are deliberately being exposed are spread out evenly over a determined timeframe and do not overwhelm the medical infrastructure.  Start a volunteer signup for exposure.
  3. Create an intake process for volunteers.  They should be tested to see if they already have antibodies.  If so, they can skip the exposure process.  If not, they would receive a kit to expose themselves.
  4. We would start with a pilot program to closely track the hospitalization, ICU, and death rates in the healthy, volunteer population.  If we find correlations with certain characteristic or health condition of a person, we would start disqualifying them from the program. 
  5. Upon dialing in the criteria, we would expand the program to push the limits of our medical equipment/staff capacity.

Parallel efforts

During the time of deliberate exposure, parallel efforts should be pursued to minimize fatalities further:

  1. Alternatives to hospitalization, ICU, ventilation should be aggressively pursued.  There should be a dedicated effort to aggressively increasing the capacity for providing the appropriate care for those that require more than home health care.
  2. Therapies to treat those that are reacting poorly to the exposure.
  3. Vaccines – this is the preferred way of acquiring herd immunity.

Voluntary program

Would healthy, young Americans volunteer to contract the corona virus?

1. There is definitely a population in the United States that believe that the reaction to the corona virus is overblown.  This population is likely to volunteer first into the program.

2. Then, there are are those who will opt to go through the program for economic reasons.  If becoming immune to the corona virus means employment opportunities and being able to pay for housing, food, and life’s essential, a significant population will make the difficult decision to volunteer for a slot.

3.  Finally, this is a way that we can protect the most vulnerable population.  There is a group of citizens that will not want to do it, but will volunteer out of a sense of duty. 

Here is how it would look by the numbers if we distribute exposure over 6-months, 9-months, and 12-months:

image imageimage

Here is a “build up plan” to give ourselves 3 months to build up hospital capacity and ICU capacity.

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According to Propublica, we have 4700 Total Hospital Beds in our region, 71% of which are occupied.  1370 are open.  Of the 650 ICU beds, 210 are open.  According to healthdata, the average hospitalization stay has been 12 days.  The average days in the ICU has been 8 days.  The chart above shows the number of hospitalizations and ICU check-ins every 3 weeks.  At the peak, we would need to handle about 1000 ICU cases per week.  We can do this by decreasing ICU stays, increasing ICU bed capacity, and diverting ICU candidates to alternative treatment.  Over the next 3 month ramp up, our efforts should be focused on:

  1. How do we increase hospital bed capacity? 
  2. How do we decrease the number of hospital days and ICU days required before discharge?
  3. How do we divert some people that require hospitalizations and ICU care to get alternative treatment?
  4. How do we train individuals to provide some level of care at home for specific corona virus symptoms?
  5. How do we increase equipment capacity?  Here are some articles on alternative equipment.  FDA, Isinnova Ventilator Alternative in Italy, MIT

This program is best administered at the local municipality level such as county or city, as each municipality has a different medical infrastructure capacity and age demographics.  Furthermore, agricultural counties/cities should move at a different pace than crowded cities.

The thought of deliberately exposing young people to a virus that will claim lives is horrific.  However, is there a better alternative that minimizes deaths and suffering than to deliberately immunize ourselves by exposing the lowest risk population?

If you are under 45, would you volunteer for exposure considering the current situation?


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