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The do-re-mi’s of COVID-19 risk assessment

Imagine perfect social distancing: Alone in an Alpine meadow, twirling joyfully, surrounded by mountains, trees, and edelweiss. Real-life social distancing? More like trying to twirl away from the guy who’s taking up the entire frozen pizza section at the grocery store without knocking over the Oreo display.

Illustration of MIT mascot Tim the Beaver standing with outstretched arms in an Alpine field with text: MIT Medical presents the Do-re-mi's of COVID-19 risk

We’ve written a lot about COVID-19 risk assessment over the last 18 months, especially as more transmissible variants of the virus have evolved. But in many ways, we’re safer than ever before. For one thing, a large proportion of the MIT community is now fully vaccinated — more than 98 percent, in fact.

But it’s not time to stop thinking about risk assessment and making safer choices.

Vaccination lowers the risk of serious illness, even while variants make breakthrough infections more likely. Members of the MIT community are tested regularly, and the positivity rate has remained low. But every positive test has a ripple effect that involves contact tracing, quarantines, inconvenience, and anxiety, because we know that vaccinated people can spread the virus. To protect vulnerable members of our community, we must continue taking precautions against exposure and infection.

That’s why MIT’s own Tim the Beaver has teamed up with MIT Medical help you learn the do-re-mi’s of COVID-19 risk assessment.

Determining the factors that increase your risk of exposure is as easy as A-B-C. Four C’s, to be exact: Closed spaces. Crowded places. Close contacts. Continuous exposure. In other words, to assess your risk of exposure to COVID-19 in any situation, you should consider ventilation, numbers, space, and time.

  1. Closed spaces. Outdoors is safest, but if you’re going to be inside, consider the size of the space and how well it is ventilated. While the CDC defines “close contact” as being within six feet of an infected individual for more than 15 cumulative minutes in a 24-hour period, documented cases of transmission have occurred in poorly ventilated and enclosed spaces between individuals who were more than six feet apart or after the COVID-19-positive person had left the area. The ventilation team from MIT’s Department of Facilities has evaluated and adjusted ventilation and air-filtration systems in all campus buildings, but you should exercise extra caution in off-campus spaces.
  2. Crowded places. The more people you are around, the more likely you are to be exposed to someone who is infected. And if other people in that space are unmasked and engaged in any activity that is likely to increase respiration — like talking, singing, shouting, eating, or exercising — that further increases the risk.
  3. Close contacts. The virus spreads from person to person, so do your best to keep your distance — especially if you’re around people who are unmasked or whose vaccination status is unknown. And wear a mask yourself!
  4. Continuous exposure. Your risk of contracting COVID-19 in any of the above scenarios increases steadily as long as you remain in that environment. Don’t put yourself in a high-risk situation unnecessarily, but if you have no choice, do everything you can to limit the time you spend there.

Now that you've learned the four C’s, feel free to shout them (alone) from the mountaintop! Or if you’d prefer not to hoof it up that high, we’ve got a poster you can share. Print one out for yourself, and you’ll be ready for any situation. Well, maybe except for getting that guy out of your way in the pizza aisle.

Take me to the poster!

This news story has not been updated since the date shown. Information contained in this story may be outdated. For current information about MIT Medical’s services, please see relevant areas of the MIT Medical website.