Contact tracing: What is it and why is it important?

Contact tracing: What is it and why is it important?

Contact tracing is the tracking of people who have been diagnosed with COVID-19 as well as the people they come into contact with. Many countries have implemented this on a large scale basis, and it has helped stop the spread. Here in the U.S., we don’t have a nationwide system of contact tracing, but that doesn’t mean it’s not a good practice to keep yourself should you contract the coronavirus.


The basics of COVID-19 spread


In order to understand contact tracing, it’s important to understand how the disease spreads and when symptoms show up. First off, when we talk about contact tracing, what does “contact” mean? It means that you are within less than 6 feet of the person who later is diagnosed with COVID-19 for a period of at least 15 minutes. Of course, there are other ways to contract it, but for the purposes of having a high risk of contracting it, these are the conditions. 


Once contact has been made, and if the virus has spread from person to person, for the vast majority of people, COVID-19 infection takes 2-14 days to show up from the point of contact. 95% of people who have been infected will have shown symptoms by 14 days out from the point of contact with someone who has it. A person is contagious starting from 2 days before symptoms show up, up until approximately 10 days after the first symptoms show up, proving their symptoms have lessened and they’ve been fever free for a minimum of 24 hours.


Contact tracing basics


We know that one is contagious for 2 days before symptoms show up. So, you should contact anyone you’ve come into close contact with for the two days before symptoms showed up.


Example Case


Let’s take a fictitious example of a person named Lisa to help put an image to all the numbers. Lisa has contracted the coronavirus but does not know it yet. It is Tuesday, August 25th. On her way to work that day, she stands in the doorway, 4 ft away from her neighbor, having a long conversation. The next day, she visits her friend. They sit on the couch and watch a show together. Two days later, Thursday, August 27th, Lisa gets her first COVID symptoms, and after a trip to her local testing center, she finds out she’s positive. She should call both her neighbor and her friend, both of whom she’s had long, close contact with, to let them know she tested positive. They should then self-isolate for 14 days from the point of contact with her. Her neighbor should quarantine for 14 days from August 25th, while her friend should quarantine for 14 days from August 26th.


Lisa herself should quarantine for 10 days from August 27th, the day she first experienced symptoms, as long as she is fever free for 24 hours (with no fever reducing medicine). 


Let’s say Lisa has a husband and 2 kids at home with her. For the household contacts of someone with COVID-19, they should quarantine for 14 days starting from 10 days after Lisa first gets sick, provided her symptoms have gone down by then and she has been fever free for at least 24 hours. 


The aim of all this is to slow the spread of coronavirus. If everyone who had contact with a known COVID patient stayed isolated for the 14 day period, the spread would be greatly slowed and it could prevent countless cases from developing. If you are diagnosed, please contact anyone you’ve had close contact with within the two days before symptoms showed up. And if someone calls you to let you know they have been diagnosed, and you have had contact with them within the 2 days before symptoms showed up, self isolate for 14 days from the date of contact. 


This link is to the Center for Disease Control website where they discuss how long to quarantine, if exposed:


Also, here is a brief video about contact tracing: