This is the third in a series on opening up safely with the goal to provide a framework for evaluating risk as states and counties begin to relax stay home orders. We first discussed How to Assess Your Risk for Severe COVID-19 Infection and How to Assess How the Safety of Your County. Today, we provide a framework for assessing the risk of an activity, and in a subsequent post, we’ll cover mitigating your risk of exposure.

We’ve now discussed evaluating your personal risk for a severe case of COVID-19 and how to figure out how safe your community is. Each person has their own individual tolerances, but the greater risk you are for severe infection and more unsafe your county is, the higher level of precaution you should take. One of those precautions is identifying activities that are within your risk limit. Activities range in risk based on a number of factors, including type of environment, number of people you will come into contact with and the length of time you spend with those individuals.

Type of Environment

The safest environment during COVID-19 is one that allows for fresh, constantly circulating air and easy maintenance of social distancing.

  • Low Risk: Outdoor areas, like a park or beach
  • Medium Risk: Large (but sparsely populated) indoor areas, like a mall or grocery store
  • High Risk: Small indoor areas, like a bar or a subway car or large indoor events with lots of people like rallies, concerts, or sporting events

Number of People

The more people you come into close contact with (fewer than six feet), the higher your risk for catching SARS-CoV-2. For example, during the peak outbreak in New York City, there were places where one in 25 people had an active infection. By limiting the number of people you come into contact with, you decrease your chance of running into someone with an infection.

  • Low Risk: 1–2 people
  • Medium Risk: 3–10 people
  • High Risk: 11+ people

Length of Time & Proximity

You need to be exposed to a minimum number of viral particles (estimated to be as few as 1000 SARS-CoV-2 infectious particles) to be infected. A person can release infectious particles while breathing, speaking, singing, coughing and sneezing to name a few modes of transmission. Staying six feet away should be the minimum, but there is some evidence that droplets can travel up to 35 feet in coughs or sneezes. By limiting the amount of time you spend with a person and keeping six feet of distance, you are reducing your chance of inhaling enough infectious particles to become infected.

  • Low Risk: Fewer than 15 second interactions, like passing on a hiking trail
  • Medium Risk: 15 second to two minute interactions, like checking out at a grocery store
  • High Risk: Longer than two minute interactions, like having dinner sitting next to someone
  • Very High Risk: Prolonged interactions around people speaking loudly or singing, or involved interactions like kissing or sex

In addition to these three factors, you should also consider how likely it is that the other people around you will be wearing masks. Masks are crucial for limiting the spread of COVID-19 from asymptomatic carriers, so if you are going to a place where people don’t adhere to mask guidelines you are putting yourself at high risk.

Think of each of these as factors as additives. A low + low + medium activity nets out to be low-medium risk. A high + low + high activity nets out to be medium-high risk.

To use this system in practice, take for example going to the beach with your household.

  • Type of Environment: Low, because you’re outside
  • Number of People: Medium, because you might get within six feet of around five people as you navigate to a less inhabited area of the beach
  • Length of Time & Proximity: Low, because you each person you pass is fewer than five seconds of interaction

Overall, an activity like this would be in the low-medium risk range.

Each person has their own risk tolerance. We encourage you to evaluate the risk factors for all activities you choose to participate in. We recommend always taking precautions to protect yourself, including wearing a mask covering both nose and mouth at all times and keeping six feet of distance from other people.

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