The Do’s and Don’t’s of Coronavirus Safety
By Don Rosenberg 5/19/2020
Professor Erin Bromage is a Comparative Immunologist and Professor of Biology at the University of Massachusetts Dartmouth specializing in immunology.
He writes regular blogs, but a recent one about avoiding the risks of coronavirus has taken off like a rocket. https://www.erinbromage.com/post/the-risks-know-them-avoid-them
For those of you who don’t have time to read 10 pages, here’s a quick summary.
Covid-19 cases are increasing across the country; things just look better because New York is finally on the downside.
As various states start to reopen, learning how you get the coronavirus will allow you to avoid wasting effort in some areas so you can focus on areas that will make a difference.
“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.”
But what about grocery stores, state parks and joggers?
Based on his experience on how infectious diseases are transmitted, he explains that the factor that is most important is the number of viral particles you are exposed to. So if the threshold is 1,000 particles, you could get 1000 in one breath, or 10 particles in 100 breaths. This is why spouses and family members are most likely to infect each other.
A single breath releases 50-5,000 particles, a cough is 3,000 and a sneeze can be as high as 200,000,000. Larger droplets fall to the ground quickly, and others hang in the air for hours.
So ten minutes of talking with someone face to face could infect you, but in a larger space like an office where an infected person has sneezed would take most of the day.
What if someone doesn’t show symptoms?
“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.”
He goes on to discuss the types of places that are responsible for the greatest number of infections using real examples.
Cruise ships? No, not even in the top 50.
High risk areas…
Meat packing plants. Densely packed workers talking loudly to each other in a cool environment that preserves the virus.
Wedding, funerals and birthday parties where people are talking close together over a period of time.
Business networking events where people spend time talking face-to-face.
Unfortunately, restaurants can be a high danger with people spending an hour or more close together in a small room. The flow of air is a factor, sparing some, infecting others.
Airflow is also a factor in an office setting with small doses of viral particles over a long period of time infecting people who are “downwind.” Six foot social distancing doesn’t matter, since the particles spread widely.
A two-hour choir performance in an area the size of a volleyball court is another example of likely infection of the entire audience.
“All these infection events were indoors, with people closely-spaced, with lots of talking, singing, or yelling. The main sources for infection are home, workplace, public transport, social gatherings, and restaurants. This accounts for 90% of all transmission events.”
“In contrast, outbreaks spread from shopping appear to be responsible for a small percentage of traced infections.”
So shopping in a retail store for a limited period of time is lower risk – as long as there is good air circulation and you maintain social distancing. But employees who spend the entire day there are at greater risk.
Outdoor activities are very low risk, especially in heat and sunlight, as the virus has been shown to die VERY quickly when exposed to UV light.
He lists bathrooms as high risk areas, so be quick and wash your hands, or wait until you get home.
This article has implications for the Reopen movement. Which activities should never have been restricted, who should wear face masks and when, and what can be done to minimize the risk when businesses do reopen?
If you use professor Bromage’s approach of dose, air circulation and time, you can see that a restaurant or bar with people close together for an hour-long meal is a problem. But eating outdoors is lower risk, and getting takeout food is even lower. Giving good quality masks to employees who will be in contact with customers all day long and making sure the area is well-ventilated will help.
A gym with a good air flow and short workouts is better, but still a problem for the staff.
Retail stores are safer with larger air volume and circulation.
Although inhaling droplets is the most direct way of becoming infected, paying close attention to virus particles remaining on surfaces is also important. He recommends that you stay careful of what you touch, don’t touch your face, nose and eyes, and wash your hands regularly and thoroughly.
I conclude from his years of immunology experience that some of the restrictions being imposed by state governors are utterly absurd and need to be lifted immediately, and other areas, such as restaurants, bars and nightclubs, will need to be restricted for some time to come.
Business models will need to change. For example, restaurants might focus more attention on outdoor seating and takeout services.
Professor Bromage was interviewed the other day about barber shops and hair salons. Here’s the video. Conclusion? “Yes” to quick barber shop cuts when the barber is wearing a mask, “Maybe” to a long hair coloring. “Yes” to the beach, swimming and outdoor dining.
The future of the coronavirus is uncertain. Some viruses seem to have a timeclock and simply die out naturally. Others recur at the same time each year. Others lose traction as more and more of the population develop antibodies, and others, like the common flu, mutate and reinfect people.
It will take more studies to find out what we’re dealing with here. In the meantime, understanding how viral particles travel and how they infect people is an important part of staying healthy and safe.