What is contact tracing, and how will it work in Texas?

A critical part of reopening America is surveillance to monitor the number of new cases each day and watch for sudden increases in numbers. Using the tried-and-true public health technique of contact tracing to slow the spread of the coronavirus will enable communities to return to some sense of normalcy including dining in restaurants, shopping and going out for movies—all critical activities for economic and social recovery.

Contact tracing involves interviewing people who have been reported as COVID-19 cases and identifying with whom they have been in close contact in the previous 14 days. Contact tracers then take this information and reach out to the contacts to inform them of the potential exposure and to verify if the contacts are experiencing any symptoms of disease. This process helps prevent the spread of disease through encouraging testing of contacts, encouraging self-isolation, and educating them on how to prevent any further spread.

From the beginning of the COVID-19 outbreak, Angela Clendenin, PhD, and Rebecca Fischer, PhD, from the Texas A&M School of Public Health’s Department of Epidemiology & Biostatistics have worked with the Brazos Valley Health District to support the epidemiologist in case interviews and contact tracing. Some of their work has helped to identify important clusters (where two or more cases can be tied back to a common case) in the community, as well as analyzing how the disease has spread in the Brazos Valley.

“Just as COVID-19 was appearing in Texas, Brazos County officials and the Brazos County Health District began discussions about how the community could stay ahead of the disease,” Clendenin said. “They reached out to the School of Public Health needing both epidemiological and emergency management support. This community supports Texas A&M and its students, and so this was an important way to give back.”

Contact tracing of COVID-19 has proven challenging, as infected individuals become infectious before they begin to show symptoms, and many people never show symptoms at all or have only mild signs that are may be consistent with seasonal allergies. As epidemiologists continue to monitor the number of new cases of COVID-19, they are looking for the number of new infections to slow. Tracking down every contact, reinforcing behaviors that break the virus transmission cycle, and increasing testing capacity and availability are the most valuable tools available at this time to preventing further increases in cases.

“Containment of the virus is essential if we are going to be able to successfully open up our communities and begin interacting again with each other in person,” Fischer said. “The large number of asymptomatic and mildly symptomatic people help facilitate the spread of this disease in the community. Since these people are less likely to visit a health care provider and be tested, they are cases that go unreported and hamper our ability to track the spread. This is a new virus, and it has proven to be severe, even fatal, for a large portion of the population, so containing the virus will protect vulnerable residents and our health care infrastructure’s ability to care for them.”

Clendenin and Fischer are members of a disease modeling team that includes Marcia Ory, PhD, Murray Cote, PhD, and Tiffany Radcliff, PhD, from the School of Public Health and Martial Ndeffo, PhD, from the College of Veterinary Medicine & Biomedical Sciences. This team has been working with both state and local officials to develop mathematical models to be used in forecasting disease spread across the state. The information from this effort is being used as an aid to decision-making for elected officials.

Now that state projections are indicting a slowing down in the rate of new cases, Fischer says it is important to know we are not out of the woods yet.

“It would appear that the increase in the number of new cases each day has slowed, but the numbers are still very high and do not show signs of decrease at this stage,” Fischer said. “The re-opening of gathering spots like beaches, malls and retail businesses with close contact between customers could lead to a rapid acceleration of the disease. We can expect an increase in the number of infections as we increase personal interaction, but we can try to control what this spike in cases will look like if we can interact responsibly. Monitoring the numbers over the next 10 to 14 days will be extremely important.”

The novelty of the disease and its persistence in communities across Texas has public health providers nervous as people go back to work and seemingly normal activities.

“This disease is highly transmissible. Anyone who has not had the disease remains susceptible to it, and it is deadly for many,” Clendenin said. “While economic recovery is very important to all of us, our ability to manage and contain this disease is a priority as we move to open up more and more parts of the state. So while it may appear as if we are ‘over’ COVID-19, do not be fooled. This disease is going to be with us for a while with some projections indicating another 18 to 24 months. Even with a vaccine, COVID-19 is likely to become endemic in our society and settle into a seasonal cycle of some sort.”