I want to share an article that, if you haven’t already come across, now is the time to read it.
As our country starts to re-open, we must act responsibly and with vigilance, and understand the risks of reopening as well as how to best avoid or minimize these risks.
Dr. Erin Bromage, a comparative immunologist and professor of biology at the University of Massachusetts Dartmouth, has written a series of posts regarding Covid-19. You may have also seen him on the news recently, as the post below went viral. In this particular article, he discusses the risks of Covid-19 spread, and uses the equation:
SUCCESSFUL INFECTION = EXPOSURE TO VIRUS X TIME
to analyze multiple scenarios of getting infected with the virus with various types and duration of exposure.
Keep in mind, enclosed spaces, where you are in close contact with people and there is poor air circulation (think household, work environment with multiple people sharing the space, transportation, large gatherings indoors), account for most of the spread. A study from China found that a large majority of infection transmission occurs indoors. Less than 0.3% of all traced infections (1 event), resulted outdoors.
Breathing, speaking, coughing and sneezing all emit viral particles into the air.
Sneezing releases the greatest number of particles into the air. If an infected person sneezes indoors, they release 200 million virus particles that can easily travel across the room they are in.
A recent study found that loud speech can result in as many as thousands of oral fluid droplets per second released into the air. In a closed, stagnant air, these droplets disappear within 8-14 minutes. High amounts of the SARS-CoV2 virus have been found in the oral fluids of individuals with Covid-19 (including asymptomatic ones!).
Some experts have estimated that exposure to around 1,000 SARS-CoV2 particles are sufficient for an individual to become infected. It is therefore clear that not only sneezing and coughing, but loud speech alone, by an infected person indoors is likely to cause an infection.
To read more about risks of being infected with SARS-CoV2 and how to reduce these risks, read Dr. Bromage’s article: https://www.erinbromage.com/post/the-risks-know-them-avoid-them
As much as we all want our work, school, social lives and group exercise classes (I miss these so much!) to go back to “normal”, this illustrates that we need to be aware of the biology of the current situation, and continue to practice wearing masks, hand washing, not touching our faces, and social distancing according to the recommendations by the CDC and public health experts. Even as a number of countries and regions re-open, we need to stay vigilant and exercise caution. This doesn’t mean that we have to be fearful, but it does mean that we can’t go from shelter in place to “pre-Covid-19” behaviors overnight.