In recent weeks, we’ve all begun to hear the words “contact tracing”– seemingly everywhere. As epidemiologists, we are constantly studying patterns, whether patterns of infection or patterns of injury, and part of that study involves contact tracing. Contact tracing is just another way of saying we trace each positive infection back to its source—or at least we try.
COVID-19 has put a bright spotlight on our work and highlighted the importance of investigating each and every case of infection by contact tracing.
Simply put, when we learn of a positive COVID-19 case, within 24 hours we follow with a very thorough process that involves investigating exposure, contacting anyone who may have also been exposed, educating each exposed person about symptoms to watch for, and if needed, self-isolating to reduce the spread.
The first step of the investigation is an interview with the COVID-positive patient so we can effectively narrow the chain of transmission. We focus on questions relating to the locations and contacts for the 48 hours before their symptoms began. What locations did they visit? What stores, restaurants, towns, and homes did they travel to? Who did they interact with and with whom were they in close contact? As you can imagine, it’s not an easy process, and the long incubation period, or amount of time between when someone is exposed, and when they may become sick, makes this even more challenging with COVID-19. Right now, given the recent stay-at-home order, you might have a pretty good idea where you were in the past two weeks. But think back to a weekend last February. Imagine all the places you may have gone and people you would have had interactions within a two week period. The list is likely long. Armed with those answers and that contact list, we develop a very comprehensive trail to follow in order to determine exposure and level of risk.
Once we know who the person has been in contact with, we begin our contact notification These conversations can be some of the most challenging. People are unsure and scared about the information we’re giving them, responding in varying ways. We see anger, confusion, desire for more information than we’re allowed to disclose, as well as relief, gratitude, and compassion. We ask every contact if they are ill, and if so, what their symptoms are.
We mentioned one of the unique challenges of COVID-19 being that relatively long (2-weeks) incubation period. That is the period from exposure to appearance of symptoms. We ask those who have been exposed and have symptoms to self-quarantine as much as they are able. That means if they can stay at home and avoid interaction with others, we strongly advise it to reduce the spread.
We also take into account the level of risk of exposure; is it high, low, or somewhere in the middle?. The risk of exposure is greatest if you’re exposed to a COVID-19 positive patient for an extended period of time. Minimal contact with someone at a far distance is less likely to result in an exposure (the reason social distancing and the use of cloth face masks are suggested strategies). If someone is classified as a low-risk exposure and does not have symptoms, they need to monitor themselves closely and stay home if they begin to develop any symptoms at all for up to 2 weeks. If a contact we talk to is considered high risk, or already has symptoms themselves, they are advised to self-isolate, and they are screened and tested for COVID-19 if they choose.
The Stay-At-Home order has certainly helped reduce the number of social gatherings and has further reduced the spread. It has also allowed us to keep our caseloads for contact tracing investigation at a manageable size. But we spend a lot of time on the phone. Think back to that list of people you could have been in contact with; there are times when we’ve had to contact up to 50 people or more who may have been exposed to just one positive COVID-19 patient. For the more than 40 positive cases in Mesa County, we’ve contacted well over 200 people.
When we as a community honor the Safer at Home guidelines, we limit the spread of the virus. We have done a phenomenal job so far. But we want you to also realize that you are our partner in this process; when you minimize social interactions you are also helping us in our work of contact tracing. By keeping contact tracing to a manageable size through minimal infections across the county, we can quickly and thoroughly investigate each and every positive case we encounter and together, we continue to keep our positive case numbers low.
We’re not through this yet, but contact tracing is a proven way to make a positive difference in our fight against the spread of COVID-19.