Going to a Christmas party? Calculate your own COVID-19 risk

COVID-19 hospitalization rate increases with age. Eight out 10 deaths are adults aged 65 years and older. Source: CDC

Should you go to a Christmas party, meet friends for a drink, continue your yoga or kickboxing classes? There are online calculators, free and easy, that can estimate your COVID-19 risk.

For example, I swim at Lakewood High School with the O*H*I*O Masters Club. I’m trying to determine if it’s safe to continue swimming given the recent acceleration in COVID-19 cases.

Question #1: What’s my chance of encountering a COVID-19- infected person during my practice?

To determine that, I used an event risk assessment tool, designed by the Georgia Institute of Technology, at covid19risk.biosci.gatech.edu.

I answered two questions: crowd size and location. Voilà, in seconds, I found that in a group of 15 people, the probability that at least one person is infected with COVID-19 is 39% (data obtained 11/26/2020). The risk is not trivial.

Question #2: What’s my risk of contracting COVID-19 during a swim practice?

I tried two calculators. The first, available at mycovidrisk.app, was developed by Brown University Alpert Medical School. More information was needed: location, setting, crowd size, nature of activities, and the percentage of people wearing masks. The estimated risk of me contracting COVID-19 after a one-hour swim practice is high (0.1 to 5%).

The calculator suggests mitigating factors: By wearing double-layered, tightly woven masks and keeping social distancing to 6 feet, I brought my risk down to low. Pretty good.

Then I tried "19 and Me," developed by a Mathematica data scientist, at 19andme.covid19.mathematica.org. My estimated weekly risk of catching COVID-19 is 1.6% if I attend three swim practices vs. 0.14% if I skip them.  

Needless to say, I had a boatload of fun. (Before you calculate my risk of turning into a certifiable geek, what fun things do you do on cold and rainy days?)

Now the real question: How seriously do I take these numbers?

I found the methodology sound, the numbers ballpark reasonable.

I learned important information. I was surprised how much my risk went up by going to swim practices – 10x. But I must admit I like Ohio’s color-coded, county-wide alert system better. First, colors are easy. Cuyahoga County, red = bad; Franklin County, purple = worse. Second, the system considers additional factors including our local hospital capacity.

More important than numbers and colors: Understand your own risk. If you (or your family, close contacts) are immunocompromised (see CDC.gov for the complete listing), I would not just consider, but do everything in the CDC and state/county advisory.

I know wearing masks is an inconvenience, but it should not be a political grievance. It’s like saying gravity is a choice.

Hard facts: SARS-CoV-2, a medium-size virus, can penetrate your cells in minutes after contact. One person – on average – infects two to three more people. With more than 260,000 deaths, it’s currently the third leading cause of death in the U.S. (behind heart attacks and cancer of all causes), and that’s 10 months in with winter ahead.

The bedrock of infectious disease control: Don’t get it. Don’t give it.

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Volume 12, Issue 23, Posted 10:03 AM, 12.01.2020