MODERATOR: Welcome to Mayo Clinic "COVID-19, Expert Insights and Strategies." The following activity is supported in part by an independent medical education grant from Pfizer Inc. and is in accordance with ACCME guidelines.

LAURA BREEHER: It's a pleasure to present on contact tracing and case investigation as part of the COVID-19 series. I'm Laura Breeher and serve as Medical Director for Occupational Health Services in Rochester, Minnesota. And I'm joined by my colleague, Dr. Caitlin Hainy, from Occupational Health Services. We have no relevant disclosures.

At the end of the presentation today, our objectives are for the audience to understand the purpose of contact tracing, appreciate the core concepts of contact tracing in case investigation as it relates to COVID-19 infection and transmission, and identify the complexities and added challenges that have to be overcome to perform effective contact tracing in healthcare setting.

I want to start by discussing what contact tracing is. In a nutshell, contact tracing is the process of identifying those who may have been exposed to an individual with an infectious disease. While many may have heard of contact tracing for the first time during the COVID-19 pandemic, it's an important public health tool that's used for many other diseases as well. Contact tracing is one of several important steps in controlling the spread of disease.

To enable contact tracing teams to identify those who may have been exposed to an individual with an infectious disease, process needs to support early detection before contacts develop and spread the disease. For COVID-19, we want contact tracing to be really fast and identify contacts early before they could spread this disease. Ideally, this is within 1-2 days of contact with an infected person, but often, they're identified as infected further out than that. We also want contact tracing to be thorough and geographically broad to include work, home, and community contacts.

The World Health Organization has provided a nice schematic outlining these steps of early detection and isolation, as well as treatment to decrease transmission within communities and workplaces and increase the survival for those who do unfortunately become infected. The overarching goal of contact tracing is to identify exposed individuals and quarantine them before the exposed individuals develop COVID and infect others. We do this to stop the spread of disease.

One thing that has become very clear during the pandemic is that modern life involves a lot of interaction with others, which can make it difficult for people to recall their movement and contacts in the event they do develop COVID-19 infection. With contact tracing, we work very hard to assist them in recalling those events.

To set the groundwork for details later in the presentation, I want to start out by discussing some of the core principles and key elements of the case investigation we perform with contact tracing. We start by contacting the person who has been identified as infected. Often this is following a COVID positive PCR test, but it can also be after a clinical diagnosis.

We work with them to recall their activities and close contacts with others during the time frame when they would have been considered critical, and then we begin contacting each of those potentially exposed individuals to perform a risk assessment. We advise whether they should quarantine and be monitoring-- monitored for symptoms as well.

Any individuals who already have symptoms are sent for testing to identify if they are infected and connected with appropriate care. Case investigation supports the COVID infected person to assist in the process of warning contacts of the exposure in order to stop the chain of transmission. I want to discuss in more detail the elements that are included in the interview with the COVID infected person.

We first determine whether they have a known exposure at work, home, or the community to identify the source of their infection, if able. We advise the employee on isolation per public health recommendations and also facilitate restrictions for work to prevent transmission. We ask about when their symptoms began, if they do have symptoms, and calculate their communicable period. For employees exposed to patients in a healthcare setting, we use electronic medical record tools, as well as work units schedules, interviews with supervisors, and other digital tools for contact tracing.

For co-worker exposures, we ask about work history and get a list of close contacts at work from both the COVID infected individual, as well as their supervisor. If the individual was at work, the supervisor interview is crucial to confirm if precautions were in place, including face masks. We then proceed with contacting those individuals who may have been exposed to assess in more detail.

We then perform a risk assessment of each employee who had close contact at less than six feet, or a prolonged period such as 15 minutes in a community setting, without all appropriate PPE. The timing of the contact is crucial. We look back 48-hours from either the onset of symptoms or the positive COVID PCR test to identify interactions with others that could have resulted in exposure from that time through the end of the [INAUDIBLE] period.

At this point, I'd like to hand it over to my colleague, Caitlin Hainy, who will discuss details of risk assessment, quarantine, isolation, as well as some of the challenges we appreciate with contact tracing.

CAITLIN HAINY: Thank you, Dr. Breeher. So when evaluating the risk of exposure for close contacts of a known COVID-positive individual, it is crucial to determine what risk level of exposure occurred. This is where personal protective equipment is so important in preventing further transmission of COVID-19 both in the healthcare setting, as well as in our communities. When interviewing close contacts of a positive patient, it's important to ascertain not only what the exposed individual was wearing for PPE but also what the infected COVID-19 positive individual was wearing at the time of close contact.

The picture shown here is a quick schematic showing the risk assessment based on different PPE configurations. You can see that if the source, or infected person, has no mask, someone in close contact at less than six feet for an extended duration of time would have a high risk exposure if they were also unmasked, a medium risk exposure if they were wearing a mask, and a low-risk exposure only if they were wearing a mask and eye protection.

If the infected individual is wearing a mask themselves, this would be considered source control, which does help reduce the risk of exposure for an unmasked contact down to medium instead of high risk and a masked contact to low risk. The determination of high, medium, and low risk of exposure will ultimately determine the outcome, management or action that will be taken for the exposed close contact.

So here you can see the risk level of low, medium, and high in the actions that will be taken based on the level of exposure at the time of contact with the COVID-19 positive individual. For those who are assessed as having a low risk exposure, for example, two people who had masks at the time of contact and later learned that one of them was communicable for COVID-19, the exposed individual can continue to self-monitor for symptoms of COVID-19 and may continue to work as well as move in the community without restriction.

However, for those who incurred a medium to high risk exposure, which would be anyone unmasked who had close prolonged contact with the COVID infected individual, would be advised to quarantine for 14 days, undergo active monitoring for symptoms with daily questionnaires, and that Mayo Clinic would be required to complete an end-of-quarantine PCR COVID-19 test to ensure we are not returning asymptomatic individuals-- asymptomatic infected individuals back to work.

So what exactly is the difference, though, between the terminology of isolation versus quarantine in correlation to COVID-19? Isolation, or the direction to isolate away from others, is provided to individuals whom are either symptomatic or displaying symptoms consistent with COVID-19 and being sent for testing, or an individual who has received a confirmed positive COVID-19 test or diagnosis and thus, is infected with the virus themselves.

Isolation is essentially used to separate people infected with COVID-19 from people who are not infected, mitigating or stopping any further spread of the virus. Individuals in isolation are directed to stay home and isolate from others in the household or in the community until they are considered no longer contagious or at risk for spreading the disease further.

Quarantine, on the other hand, is used for asymptomatic individuals who have been exposed to a confirmed case of COVID-19 or traveled to an area possibly with high prevalence of an infectious disease and may have been exposed. Quarantine helps prevent the spread of disease that can occur before the person even knows they are sick or have been infected with the virus without feeling symptoms, again, helping to prevent the spread of infection in the event that an infection develops after significant exposure.

Individuals in quarantine must stay home, separate themselves from others, and monitor for symptoms consistent with COVID-19. The duration of quarantine for COVID-19 will last up to 14 days from the last known date of exposure or during the full 14-day incubation period.

When performing contact tracing, there are essentially four key steps to remember. One, we need to test widely for the virus. We need to find people who are infected, including those who may be asymptomatic and spreading the virus unknowingly. Two, we need to isolate individuals infected with the virus, or those displaying symptoms consistent with COVID-19, and separate them from those who are not infected.

Three, we need to identify everyone who has been in contact with the infected individuals and potentially exposed. And four, we need to quarantine those who have been in close contact with infected individuals for up to 14 days from the date of their last known exposure. They should not leave home and should avoid close contact with other members of their household. Remember, infected individuals shed a lot of infectious virus even before they have symptoms, so quarantine of contacts is critically important in slowing the spread of COVID-19.

Why, then, is contact tracing for COVID-19 so challenging? As we previously shared, when discussing the importance of quarantine, one of the biggest challenges with COVID-19 is that the infected individual may spread COVID-19 before they develop symptoms or know they have become infected. In fact, the COVID-19 virus can be shared two days before symptoms onset with the peak of infectious period occurring in approximately one day before symptoms develop.

Because infected individuals may feel well and look well, they are likely not to limit their normal daily activities or perhaps follow the recommended precautions of social distancing and wearing a mask in shared spaces, therefore potentially exposing many during that asymptomatic period of communicability.

We know the incubation period of COVID-19 is between 2-14 days after the last known date of exposure, and that most COVID infections will develop, on average, between 5-7 days during that 14-day incubation. Since the test turnaround times in many areas can be longer than the minimum incubation period, by the time an individual tests positive, they have likely been communicable for an average of 4-5 days, thus highlighting why it is so critically important to start contact tracing as soon as we are notified of any new COVID positive cases.

Contact tracing must be initiated quickly to ensure potentially exposed individuals are made aware of their exposure and the right steps are taken to quarantine these individuals away from others or be tested themselves if they are displaying symptoms of COVID-19. Essentially, we need to get in front of the moving train and stop the virus before it leaves the station or travels to another area to expose uninfected individuals.

Further adding to the complexity of contact tracing, though, is the challenges of contact tracing within the healthcare setting. As the pandemic has progressed and the critical importance of contact tracing has been emphasized, many technology teams have attempted to develop digital contact tracing tools to assist with early and quick identification of close contacts to a COVID-19 case. While this may be a potential and viable option within the community settings, many of these digital tools are only 2D and therefore, cannot accurately identify contacts within the 3D layout of a large hospital or healthcare setting.

Such tools may detect what appear to be two individuals standing next to each other, when in reality, they are standing on separate floors with either a ceiling or floor in between and never come in close contact with each other throughout the day. These tools also rely on user adoption of the technology and are only good if used by all potentially exposed contacts, therefore, not eliminating the need to identify, notify, and evaluate all exposed individuals.

The historic workflow in healthcare also poses a challenge with large teams involved in each patient's care, large teams rounding, or shift change handoff occurring in close proximity and shared workspaces or team work rooms used by multiple staff throughout the day. Many facilities have space constraints, including crowded cafeterias, break rooms, or work rooms where staff must remove their masks at times, such as eating lunch, but due to the space constraints, are unable to socially distance from others.

And scheduling of employees can become increasingly complex with float staff rotating through several different units often multiple times during one scheduled shift, alternating schedules or rotating shifts with new team members, and employees who have multiple jobs and may be moonlighting in skilled nursing facilities or critical access hospitals in adjacent communities, all of these posing an increased risk of new exposure and further spread of COVID-19.

Now that we've explained the purposes of contact tracing, described the core concepts and general considerations, let's put it all together by walking through a brief case of a real life situation. An impatient nurse working in direct patient care presented to work on Monday morning feeling well with no concerns. However, halfway through her shift, she developed new onset of headache and sore throat. She called her local occupational health services nurse line, was instructed to leave work early, isolate away from others, and sent for a COVID-19 PCR test.

Unfortunately, the test did return positive the following day, and she was, in fact, infected with COVID-19. A member of the exposure investigation team was alerted to the new employee positive test result and called the nurse to interview her and ask about any close contacts with other employees or patients that may have occurred during the 48-hour communicable period and symptomatic period.

Upon interview, it was found that the nurse was part of the float staff and had worked several shifts during the 3-day communicable period across many different units. Fortunately, she and her co-workers were diligent about masking at work, so there were no medium or high risk occupational exposures from her workplace contact.

However, we also learned that she had carpooled to work with two other co-workers and had to remove her mask as her glasses were fogging while driving. She had also gone to dinner with a group of coworkers during the communicable period, and her spouse had been ill the week prior after traveling by plane on a domestic flight.

During the investigation, it was discovered that she also had many close contacts in the community and her neighborhood of whom also worked in healthcare. All of the identified close contacts received their own follow-up phone call from the exposure team for their individual exposure assessment and risk level determination.

While many were low risk because they were never less than six feet away or were wearing the appropriate PPE, several close contacts met criteria for high risk exposure as masks were not used, and they were advised to quarantine and restricted from work on campus for 14 days from the last known date of contact. A few of the close contacts were already reporting symptoms at the time of the phone call, were asked to isolate away from others, and sent for testing.

Of the employees evaluated as part of this exposure, three went on to test positive for COVID-19. So as you can see in this example, contact tracing can be time consuming and requires some astute investigational skills but is critically important in mitigating and slowing the further spread of COVID-19.

To close in summary, contact tracing is a critical tool to public health in suppressing COVID-19 with the goal of stopping the spread of disease by identifying those who may have been exposed to an individual with an infectious disease early, assessing the risk of exposure and potential for disease transmission including onset of symptoms, and facilitating quarantine for those with an elevated risk of exposure before they infect others.

Remember-- test, isolate, identify, and quarantine. We may not be able to completely eliminate the-- eliminate COVID-19, but with contact tracing, we can slow the spread of disease and keep our communities open. Here are our references for today's presentation. And on behalf of Dr. Breeher and I, we would like to thank you all for your time and attention during today's presentation.