Friday, June 12, 2020

Settings that Heighten Risk for SARS-CoV-2 Transmission

Photo by diofw
Because I want to better understand the risk factors for coronavirus (aka COVID-19 the disease, SARS-COV-2 the virus), I wrote a post in April about biological risk factors such as obesity and diabetes. I'm adding to that post as new risk factors are announced (such as blood type).

Basically, these elements increase risk of COVID-19 transmission:
  • Being INDOORS (less ventilation of fresh air, more risk)
  • Being in a CROWDED space (closer to people, more risk)
  • LINGERING in that space over times (more time, more risk)
  • Being in a county with a HIGH INFECTION RATE (more community infection, more risk)
  • Being in a crowd WITH TRAVELERS from many other locations (more counties, more risk)
  • Being in a crowd where people PROJECT THEIR VOICE OR BREATH by talking, cheering, yelling, crying, booing, singing, panting, coughing, sneezing (more people exhaling forcefully with high frequency, more risk)
The date of this post is June 12th, but as I read news stories and scholarly studies, I will be adding information about settings that are high risk factors for transmission.

UPDATE:  I stopped updating this post one the fall semester started, and I was teaching 36 university students on Zoom. They needed a lot of support, so I shifted a lot of my energies there.  Sixteen of these students were assigned to read scholarly journals on SARS-CoV-2 and COVID-19, so I got to read annotated bibliographies about the pandemic for well over 100 research articles.  

This post serves more as a record of my efforts in the summer to understand risk factors. 

Science is an activity that is constantly in motion. New data has emerged (and will continue to emerge).  Check the CDC webpage and evidence-based medicine in peer-reviewed medical journals (such as JAMA, NEJM, Lancet, and BJM) for emerging data. There are also great scientific journals, but these four (two from the US and two from the UK) are a good place to start.

Graphic artists are doing a MUCH BETTER JOB than I in representing risks (but they don't have nursing homes, prisons, jails or meat packing plants listed on them).

July 3, 2020 The Texas Medical Association released this graphic.

The HIGH RISK activities are listed as

* Going to a bar
* Attending a religious service with 500+ people
* Going to a sports stadium
* Attending a large music concert
* Going to a movie theater
* Going to an amusement park
* Working out at a gym
* Eating at a buffet

Click on this link to read the full chart for other risky activities.

Information Is Beautiful @InfoBeautiful combined information from a variety of sources to make this graphic.

The highest risk activities on this data viz are as follows:

* nightclub
* indoor bars
* churches (particularly because of the singing)
* concert
* play
* indoor party
* sports arenas
* buffet
* amusement park
* wedding / funeral
* hug / shake hands
* socialize with strangers

On June 30, 2020, Doctors Emanual, Popscue & Phillips developed this guideline that assigns various activities a level of risk for contracting COVID-19.

The activities with the highest level of risk on this index are as follows:

* Indoor parties
* Playing contact sports
* Bars and nightclubs
* Public transportation
* Air travel
* Concerts
* Theaters (live or movie)
* Watching sports
* Religious Services

This 6/18/20 Science  News article has a very good data viz for depicting risk of spread. The bubbles in the graphic are hyperlinked.
Click the image to visit the Science News interactive graphic
Physical Settings that Heighten Risks

Congregate Living. Many indoor settings where people are in close contact are proving to have high transmission rates, such as congregate living:
Workplaces. Also, workplaces where people are in close proximity and often with a lot of talking either because of noise or because the work being done is talking.
Here is a list of several occupations and the estimated risk--with dental hygienist as being listed as a high risk for infection.

I am a university teacher, so I worry about lecturing and class discussion being acts of transmission within crowded, enclosed classrooms. For this reason, I am moving my classes online for Fall 2020--particularly since my spouse has multiple chronic diseases that heighten risk for a severe case of COVID-19.

Sporting events: the players
Churches and Church Activities
Recreational Activities. Activities that focus on exhaling strongly indoors increase risk, which include:
Air Pollution
Outdoor Transmission. This seems to be rare. See this Lake of the Ozarks news story. We will have to see if the protests of late May, early June result in an uptick of cases.

Social (Economic, Education, Healthcare, etc.) Inequalities

Unfortunately, a number of people are at higher risk because of systemic inequalities, including people of color, particularly Native Americans. These are not because of biological factors (excepting perhaps sickle cell anemia, since blood disorders are a risk factor, and African Americans have a higher rate of sickle cell anemia).

The virus is exposing gross inequalities that our must address by offering greater resources and working for a more just society across the life span in order to erase cumulative disadvantage that comes with systemic racism.

This is another topic I'd like to learn about, so I will probably write a post about this, particularly as COVID-19 is affecting black, Hispanic, and Native American older adults in the US.


Biological Risk Factors for COVID-19


  1. This is an interesting post containing food for thought, as the saying goes. I am concerned that the protests may cause outbreaks of the virus across the country. Sometimes behavior leads to outbreaks.

    1. Terra: Yes, I am watching the stats every day to see if there are spikes. All my best to your and yours for staying healthy.

  2. Yes, thank you for sharing. I attended a BLM March and protest and then was tested a few days later - thankfully the results were negative.

    1. Antionette: I do agree that raising awareness of the health risks of systemic racism is worth the exposure. Also, protests were outdoors, and from the videos and photos I saw, many people were wearing masks. I'm glad you are safe and working to promote the safety of others. #BLM

  3. Thank you, Karen for your knowledge and your research. It is so nice to have a place I know I can go for accurate data during this time of common misdirection!

    1. Diane: My husband has several risk factors, so I'm trying to read what virologists, infectious disease specialists and epidemiologists have to say about COVID-19. The science of all this is still emerging. All my best to you and yours.