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Map shows county-by-county risk of encountering COVID-19 at an event

With the holiday season here, you may be tempted to go to a gathering. A map can assess your risk.

HOUSTON — COVID-19 cases are skyrocketing across the country. We’re also moving into the holiday season, a time that friends and family traditionally get together, which could lead to many more infections.

According to the CDC, the lowest risk for you and your family this holiday season is by celebrate virtually only with loved ones outside your household and limit your in-person contact to people who already live under your roof.

Just one confirmed case at a gathering can lead to many more infections, but what is your risk of being exposed if you attend an event or get-together outside your household? An assessment map put together by Georgia Tech is tracking your risk, based on where you are and how many people are at a gathering or event.

CHECK THE MAP: This map can assess your risk of being exposed at a gathering

The interactive map allows users to choose a county anywhere in the United States, select the event size (anywhere from 10 people to 5,000) and then calculate the risk that at least one COVID-19 positive person will be present.

RELATED: Texas becomes 1st state to surpass 1 million COVID-19 cases

For example, in Harris County, the tool calculates that at a 50-person event, there is an 34-percent chance that someone in attendance will be infected with COVID-19. At a gathering with only 10 people, that risk goes down to 8 percent.

But if you’re visiting family in El Paso County, which has seen a major surge in cases in recent weeks, the chance of at least one person at a 10-person gathering having COVID-19 jumps to 65 percent. If the gathering in El Paso County has 50 people, the chance is more than 99 percent.

The risk assessment tool was developed by researchers at Georgia Tech's Institute of Technology, Biological Sciences (GT-BIOS) and the Applied Bioinformatics Laboratory (ABiL). 

The interactive map is based on data from The COVID Tracking Project at The Atlantic, which pulls daily data on COVID-19 testing and patients from all 50 states. It's also based on 2019 U.S. Census data.

“We're viewing this tool a little bit like a weather map in that we're not necessarily telling you the chance that you're getting going to get wet,” said Georgia Tech Asst. Professor Clio Andris.

“But we are telling you sort of more of the chance that it’s raining.”

In other words, Andis said the data does not account for who is wearing a mask, whether they’re physically distancing or if the event is indoors or outside.

But the map, and the math behind it, can help would-be travelers make informed choices on whether or not to go.

“The cases are surging right now. And if we have any hope of getting these rates back down, we've got to make these tough decisions,” Andris said.


CDC guidelines for keeping your COVID-19 risk low during holidays

Below in information directly from the Centers for Disease Control regarding holiday gatherings.


Celebrating virtually or with members of your own household (who are consistently taking measures to reduce the spread of COVID-19) poses the lowest risk for spread. Your household is anyone who currently lives and shares common spaces in your housing unit (such as your house or apartment). This can include family members, as well as roommates or people who are unrelated to you. People who do not currently live in your housing unit, such as college students who are returning home from school for the holidays, should be considered part of different households. In-person gatherings that bring together family members or friends from different households, including college students returning home, pose varying levels of risk.

Organizers and attendees of larger events should consider the risk of virus spread based on event size (number of attendees and other factors) and take steps to reduce the possibility of infection, as outlined in the Considerations for Events and Gatherings.

There are several factors that contribute to the risk of getting and spreading COVID-19 at small in-person gatherings. In combination, these factors will create various amounts of risk:

  • Community levels of COVID-19 – High or increasing levels of COVID-19 cases in the gathering location, as well as in the areas where attendees are coming from, increase the risk of infection and spread among attendees. Family and friends should consider the number of COVID-19 cases in their community and in the community where they plan to celebrate when deciding whether to host or attend a gathering. Information on the number of cases in an area can often be found on the local health department website.
  • Exposure during travel – Airports, bus stations, train stations, public transport, gas stations, and rest stops are all places travelers can be exposed to the virus in the air and on surfaces.
  • Location of the gathering – Indoor gatherings, especially those with poor ventilation (for example, small enclosed spaces with no outside air), pose more risk than outdoor gatherings.
  • Duration of the gathering – Gatherings that last longer pose more risk than shorter gatherings. Being within 6 feet of someone who has COVID-19 for a cumulative total of 15 minutes or more greatly increases the risk of becoming sick and requires a 14-day quarantine.
  • Number and crowding of people at the gathering – Gatherings with more people pose more risk than gatherings with fewer people. CDC does not have a limit or recommend a specific number of attendees for gatherings. The size of a holiday gathering should be determined based on the ability of attendees from different households to stay 6 feet (2 arm lengths) apart, wear masks, wash hands, and follow state, local, territorial, or tribal health and safety laws, rules, and regulations.
  • Behaviors of attendees prior to the gathering – Individuals who did not consistently adhere to social distancing (staying at least 6 feet apart), mask wearing, handwashing, and other prevention behaviors pose more risk than those who consistently practiced these safety measures.
  • Behaviors of attendees during the gathering – Gatherings with more safety measures in place, such as mask wearing, social distancing, and handwashing, pose less risk than gatherings where fewer or no preventive measures are being implemented. Use of alcohol or drugs may alter judgment and make it more difficult to practice COVID-19 safety measures.