Risk Management and Resuming “Normal” Life
Risk Management: A Primer
Risk management is a topic we address with clients.
We talk about three basic ways to deal with risk:
-Retain
-Mitigate
-Transfer
More typically tactics used to address a risk are a combination of the three.
Transference is where we use insurance companies to transfer the impact of low probability high cost events (your house burning down). Most of the time spent in this article will be on deciding how much risk we choose to retain and what mitigation steps we may take related
to that level of risk.
Each person’s ability to tolerate risk is unique based on their beliefs and experience, so the degree to which we adopt any of these tactics depends on each specific situation.
The key with any risk is to understand it and the range of potential outcomes (to the extent possible) and options to reduce the impact of negative outcomes so we can make educated decisions on the best course of action.
Returning to Normal Activities
With the exception of a few of my trusted experts (like Dr. Scott Gottlieb), the mainstream media has not let us down with their typical sensationalism and agenda. I literally saw on the same day an article from CNN basically implying this was the equivalent to leprosy while Fox News was touting that a lab in California had already come up with a therapeutic that would inoculate against the virus – no vaccine needed. I’ve seen no corroboration for either of these assertions from any reliable source since.
So, in preparation to resume my normal activities (such as returning to the gym), I thought I would do some of my own work on where the primary risks of transmission lie and the appropriate mitigation steps based on current data.
I’ve included the highpoints of what I’ve found mostly around Dr. Erin Bromage’s, a comparative immunologist and biology professor at the University of Massachusetts, Dartmouth, work. More details can be found by following the links below - including some cool diagrams of mass infection events and experiments that have been done to see how germ particles spread using blacklights.
Cliff Notes Version
If you are sick of hearing about this (frankly like I am) and don’t feel like reading the full diatribe, here is the Cliff Notes version.
1. The formula: Successful Infection = Exposure to Virus x Time
“The exposure to virus x time formula is the basis of contact tracing. Anyone you spend greater than 10 minutes with, in a face-to-face situation, is potentially infected. Anyone who shares a space with you (say an office) for an extended period is potentially infected.”
2. The Graphic
“We know most people get infected in their own home. A household member contracts the virus in the community and brings it into the house where sustained contact between household members leads to infection.”
“Social distancing rules are really to protect you with brief exposures or outdoor exposures. In these situations there is not enough time to achieve the infectious viral load when you are standing 6 feet apart or where wind and the infinite outdoor space for viral dilution reduces viral load. Social distancing guidelines don't hold in indoor spaces where you spend a lot of time.”
“Grocery stores, bike rides, inconsiderate runners who are not wearing masks.... are not really places of concern.”
“Indoor spaces, with limited air exchange or recycled air and lots of people, are concerning from a transmission standpoint. Any environment that is enclosed, with poor air circulation and high density of people, spells trouble.”
“The biggest outbreaks are in prisons, religious ceremonies, and workplaces, such as meat packing facilities and call centers.”
“Based on infectious dose studies with other coronaviruses, it appears that only small doses may be needed for infection to take hold. Some experts estimate that as few as 1000 SARS-CoV2 infectious viral particles are all that will be needed.”
“Infection could occur, through 1000 infectious viral particles you receive in one breath or from one eye-rub, or 100 viral particles inhaled with each breath over 10 breaths, or 10 viral particles with 100 breaths.”
For those interested in the details…here we go.
I. Surface vs Person to Person Transmission
Are you more likely to contract the virus from touching a contaminated surface or interacting directly with a person? That was a big question early on. It seems evidence now points mostly to person to person droplet spread, so person to person contact carries significantly more risk than simply touching something someone else has.
However, consensus remains surface or fomite contamination is still possible.
A. Surface or Fomite Transfer
We’ll take the more innocuous path to infection first and spend less time here.
“Based on data from lab studies on COVID-19 and what we know about similar respiratory diseases, it may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes, but this isn’t thought to be the main way the virus spreads.” - CDC 05/22/20 Update
“Studies show that coronavirus can last up to three days on plastic and steel, but once it lands on a surface, the amount of viable virus begins to disintegrate in a matter of hours. That means a droplet on a surface is far more infectious right after the sneeze — not so much a few days later.” Remember the formula.
“What they’re saying is that high touch surfaces like railings and doorknobs, elevator buttons are not the primary driver of the infection in the United States,” said Erin Bromage, “But it’s still a bad idea to touch your face. If someone who is infectious coughs on their hand and shakes your hand and you rub your eyes — yes, you’re infected.”
“But while those experiments show how germs can spread on surfaces, the microbe still has to survive long enough and in a large enough dose to make you sick. Eugene M. Chudnovsky, a professor at the City University of New York, notes that surfaces are not a particularly effective means of viral transmission. With the flu, for instance, it takes millions of copies of the influenza virus to infect a person through surface-to-hand-to-nose contact, but it may take only a few thousand copies to infect a person when the flu virus goes from the air directly into the lungs.”
“There’s a long chain of events that would need to happen for someone to become infected through contact with groceries, mail, takeout containers or other surfaces,” said Julia Marcus, an infectious disease epidemiologist and assistant professor in the department of population medicine at Harvard Medical School. “The last step in that causal chain is touching your eyes, nose or mouth with your contaminated hand, so the best way to make sure the chain is broken is washing your hands.”
Mitigation Steps to Avoid Surface Transmission
These are pretty straight forward.
To avoid being infected by surface (fomite) transmission:
-Don’t touch your face. This is an easy mitigation step after you catch yourself reaching to scratch your eye in public a few times.
– Wash your hands. The ultimate mitigation is what grandma has been recommending since we were children
-Avoid buffet’s and community meals, dentists and doctor’s offices or anything someone else touches that will go directly into an orifice on your head.
B. Person to Person Transmission (From Least to Greatest Risk)
Direct interaction with a virus carrier is by far the greater biggest risk.
These break down into two primary types asymptomatic and those showing symptoms.
1. The Asymptomatic
“We know that at least 44% of all infections--and the majority of community-acquired transmissions--occur from people without any symptoms (asymptomatic or pre-symptomatic people). You can be shedding the virus into the environment for up to 5 days before symptoms begin.”
“The amount of virus released from an infected person changes over the course of infection and it is also different from person-to-person. Viral load generally builds up to the point where the person becomes symptomatic. So just prior to symptoms showing, you are releasing the most virus into the environment. Interestingly, the data shows that just 20% of infected people are responsible for 99% of viral load that could potentially be released into the environment.”
a. Breathing
“A single breath releases 50 - 5000 droplets. Most of these droplets are low velocity and fall to the ground quickly. There are even fewer droplets released through nose-breathing. Importantly, due to the lack of exhalation force with a breath, viral particles from the lower respiratory areas are not expelled.”
“Unlike sneezing and coughing which release huge amounts of viral material, the respiratory droplets released from breathing only contain low levels of virus. Using influenzas as a guide something around 33 virus particles per minute.”
“With general breathing, 20 viral particles minute into the environment, even if every virus ended up in your lungs (which is very unlikely), you would need 1000 viral particles divided by 20 per minute = 50 minutes.”
Wearing a mask may be a useful mitigation step, but inhabiting the same space for a short period of time with another person who is simply breathing isn’t an overly risky endeavor.
b. Speaking
“Speaking increases the release of respiratory droplets about 10 fold; ~200 virus particles per minute. Again, assuming every virus is inhaled, it would take ~5 minutes of speaking face-to-face to receive the required dose.”
If you are going to speak face to face with someone:
-Maintain adequate distance of 6 feet or more
-It is likely prudent in this case for both parties to be wearing masks mostly to protect one another from what the speaker may be expelling
c. Singing
“Singing, to a greater degree than talking, aerosolizes respiratory droplets extraordinarily well. Deep-breathing while singing facilitated those respiratory droplets getting deep into the lungs.”
“The community choir in Washington State. Even though people were aware of the virus and took steps to minimize transfer; e.g. they avoided the usual handshakes and hugs hello, people also brought their own music to avoid sharing, and socially distanced themselves during practice. They even went to the lengths to tell choir members prior to practice that anyone experiencing symptoms should stay home. A single asymptomatic carrier infected most of the people in attendance. The choir sang for 2 1/2 hours, inside an enclosed rehearsal hall which was roughly the size of a volleyball court.”
“Two and half hours of exposure ensured that people were exposed to enough virus over a long enough period of time for infection to take place. Over a period of 4 days, 45 of the 60 choir members developed symptoms, 2 died. The youngest infected was 31, but they averaged 67 years old. (corrected link)”
For my risk tolerance, this is too great. Until there is a vaccine, an appropriate mitigation technique is avoidance of engaging in any activity where singing will take place (church, choir practice etc).
2. Symptomatic
The previous interactions are of those who were likely asymptomatic. While 44% of transmissions are believed to have occurred from asymptomatic carriers, the ability to really spread contamination would seem to occur from those showing symptoms.
a. Cough
When someone is coughing, the situation contains significantly more risk because showing symptoms like a cough, they are more likely to be a virus carrier and with a cough it is significantly easier to spread virus across larger areas.
“A single cough releases about 3,000 droplets and droplets travel at 50 miles per hour. Most droplets are large, and fall quickly (gravity), but many do stay in the air and can travel across a room in a few seconds.”
If you are coughing, for any reason, a mask is appropriate to protect others from what you may be expelling - virus or the common cold.
You should also avoid interaction with others and certainly leaving your home should be avoided by using delivery of essentials and other appropriate means until you are no longer symptomatic.
From a receiver perspective, there is always the risk of being coughed on, so a mask is an appropriate mitigation technique.
b. Sneeze
Oooh mana….a sneeze is the Queen Mary of risk in personal interaction.
“A single sneeze releases about 30,000 droplets, with droplets traveling at up to 200 miles per hour. Most droplets are small and travel great distances (easily across a room).”
A sneeze may happen out of the blue whether you are symptomatic or not. Wearing a mask in public is both courteous and appropriate to avoid transmitting or receiving the ill effects of a sneeze.
This grossed me out. “If a person is infected, the droplets in a single cough or sneeze may contain as many as 200,000,000 (two hundred million) virus particles which can all be dispersed into the environment around them.”
“Even if that cough or sneeze was not directed at you, some infected droplets--the smallest of small--can hang in the air for a few minutes, filling every corner of a modest sized room with infectious viral particles. All you have to do is enter that room within a few minutes of the cough/sneeze and take a few breaths and you have potentially received enough virus to establish an infection.”
Basically, “Your sneezes and your coughs expel so much virus that you can infect a whole room of people.”
This is the case for wearing a mask. If you are a carrier, the inside of that mask will look like a crime scene under the appropriate magnification, but it will have reduced the amount of virus emitted into the atmosphere.
II. Areas of Risk (From Least to Greatest)
A. Outdoors
“Of the countries performing contact tracing properly, only a single outbreak has been reported from an outdoor environment (less than 0.3% of traced infections).”
The impacts of sunlight, heat, and humidity (all three of which we have plenty of in Charleston) on viral survival, all serve to minimize the risk to everyone when outside.
On most nights I go for a walk in the neighborhood after I’ve finished working. I don’t wear a mask, but I will not engage in conversation with a neighbor in proximity of six feet or closer which most observe.
“If outside, and you walk past someone, remember it is “dose and time” needed for infection. You would have to be in their airstream for 5+ minutes for a chance of infection” (unless they rudely cough or sneeze on you which would be a major faux pau even in the most basic circles).
B. Shopping
Outbreaks spread from shopping appear to be responsible for a small percentage of traced infections.
“The principle is viral exposure over an extended period of time.”
“When assessing the risk of infection (via respiration) at the grocery store or mall, you need to consider the volume of the air space (very large), the number of people (restricted), how long people are spending in the store (workers - all day; customers - an hour). Taken together, for a person shopping: the low density, high air volume of the store, along with the restricted time you spend in the store, means that the opportunity to receive an infectious dose is low.”
Admittedly, I don’t do a lot of the shopping. Although, while we were building the deck, Lowe’s was my second home. If went on a weeknight, I rarely wore a mask. On a busy Saturday morning, I absolutely did. In Charleston, I was in the vast minority of those wearing masks. In fact, it is pretty rare I see people wearing masks when out which increases risk of transmission in and of itself.
During all my visits, I still kept an appropriate distance from anyone in the store and used sanitizing wipes for my hands before getting in the car. The wipes were probably overkill in hindsight of the surface data.
C. Public Restrooms
Uggh! The public restroom. Bane of my existence, but necessary.
“Bathrooms have a lot of high touch surfaces, door handles, faucets, stall doors. So fomite transfer risk in this environment can be high. Toilet flushing does aerosolize many droplets (which may or may not contain virus particles).”
Stick with the old rule of go before you leave and avoid unless it’s an emergency.
On stops between here and our trips to the mountains, gloves and hand wipes have been our mitigation steps.
D. Airplanes
What about airplanes? This was a big one for me as mom’s birthday is coming up and I usually fly up to spend it with her.
I was very surprised to learn that the airplane itself (forget about what you have to go through to get to one – similar risks to shopping and restroom) is likely more sanitary than most other environments – despite most times smelling like an old wet shoe (to be kind).
“On modern Boeing planes (others may be the same), the entire air volume of the cabin is exchanged with outside air every 4 to 5 minutes (12 to 15 cabin air exchanges per hour).
Additionally, the cabin air is filtered through a HEPA filtration system 25-30 times per hour.” HEPA you say? You have my attention.
As a point of reference:
HEPA Filters: are required to capture 99.97% of all particles >0.3 micrometers.
N95 respirators: are required to capture 95% of all particles >0.3 micrometers
“The HEPA filters in a plane have a higher filtering capacity than the N95 masks doctors and nurses are wearing when they are caring for COVID-19 patients. Granted, the respirators filter 100% of inhaled air, but the point is, aircraft have a substantial air filtration capacity.”
Dr. Bromage also discovered that, “The design of the air filtration systems on planes divides the planes up into zones of about 5-7 rows per zone. The bigger the plane, the more zones.
Basically, the plane is divided up into air compartments so the emissions from someone 10 rows behind you is going to have little effect on you due to the zoning, filtration, and air exchange.” And, “The little air nozzle above your head shoots our air directly from the HEPA filter. Directing that airstream on you increases the amount of HEPA-purified air you are inhaling. Turn it on!”
Dr. Bromage talked about traveling to Australia to see his elderly folks in one of the articles and his mitigation techniques were making the kids (and himself) keep their hands inside the cuffs of their hoodies to prevent them from touching things, lots of handwipes (which got them stopped at TSA) where contact couldn’t be avoided, and a change of clothes in their carry on bag to avoid cling-ons to their clothing from the plane making the trip in the car.
They made it all the way to Australia (21 hour flying time) and back to Boston in March without being infected or infecting anyone else.
Prior to reading this, I had ruled out the trip to Michigan next month to see the folks primarily out of caution of infecting them. After reading, I’m considering it again.
Conclusion
So that’s pretty much it. Hopefully this helps in assessing the level of risk you are comfortable with and appropriate techniques to address.
For more info and really cool visuals of outbreaks, check out the source material at the links below.
And of course, be well.
Jason
Read more of Dr. Bromage’s worh at https://www.erinbromage.com/
