Contact tracing: disease detectives in action

NCSE Director of Teacher Support Lin Andrews explains what contact tracing is and why it should be utilized as economies around the world reopen.

Yarn representation of a network.

Photo by Omar Flores on Unsplash

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Will contact tracing help ensure people’s safety as shelter-in-place orders are easing up throughout the world?

The quick answer is both yes … and no. Wow, that was helpful, wasn't it? Let me break it down by using the nature of science—and the scientific process—as our guide. But, first, let's make sure we're all on the same page as to what contact tracing is in the first place.

According to the Centers for Disease Control (CDC), contact tracing is an important disease-control measure that has been used for years by health officials and their departments to trace and monitor who has come into contact with individuals infected with a disease under investigation. In this case, COVID-19 is the culprit and, to quote one of my favorite fictional superheroes, the game is afoot!

As with any sound scientific investigation, research is an essential tool. Contact tracing is a multifaceted science endeavor that will require thousands, if not tens of thousands, of investigators to pull it off on a national scale.

Say again? Tens of thousands?

Yes. Public health "disease detectives" will have to work with individual patients to identify every single person with whom they came into close contact while they were actively contagious with COVID-19. Once they have compiled this list, public health officials must reach out to all those people to warn them of the possible risks associated with exposure. Additionally, similar lists must be compiled of the people with whom these people came into close contact. And so on.

How hard could it be? Right now, with shelter-in-place orders still active (to some degree) in most parts of the country, contact tracing has been fairly sustainable. According to George Rutherford of the University of California, San Francisco, under current conditions, each new COVID-19 case documented usually only has about five contacts that need tracing. But once "normal" life resumes, people in urban settings could easily come in contact with up to a thousand people a day.

Especially under such more difficult conditions, documentation—another essential element of the scientific process—is crucial. Follow the evidence, confirm the evidence, re-confirm the evidence, catalog the evidence, and work to draw conclusions firmly based on the evidence. The scientific process at its finest.

Teachers have been discussing the contact-tracing strategy for years while educating students about epidemiology, viruses, microbiology, and public health.

While cumbersome, this method has been successful in tracking multiple disease outbreaks by local public health authorities, the CDC, and the World Health Organization for years. However, the scale of the COVID-19 pandemic can make investigators feel like they are untangling the world's largest ball of twine!

Teachers have been discussing the contact-tracing strategy for years while educating students about epidemiology, viruses, microbiology, and public health. In fact, since 1999 the Science Olympiad (a multi-event science competition for students in grade 3 through 12) has included a tournament called Disease Detectives, developed in partnership with the CDC. Be sure to check out the CDC's great practice materials for possible activities that could be implemented in your classroom. Also, PBS Learning Media has a helpful lesson plan called Epidemiologists: Disease Detectives tied to the legendary John Snow and the famous cholera outbreak of 1854. Two other favorites of mine for the classroom are Tufts University's The Great Diseases unit on infectious diseases and HHMI's Ebola: Disease Detectives activity.

So back to our initial question: Will contact tracing help ensure people's safety as shelter-in-place orders are easing up throughout the world? The answer is still both yes and no. Yes, in that contact tracing has the potential to be one of the most powerful weapons we have to mitigate the spread of COVID-19 as we reopen our country. No, in that it cannot be the only weapon in our arsenal. In order for contact tracing to be effective, other measures also have to be put into place: (1) intensive testing; (2) isolation of infected individuals; and (3) self-quarantining of all individuals located via contact tracing for 14 days whether or not they are exhibiting symptoms.

Box It In diagram

But, wait—how can I be so confident that a contact-tracing strategy will work?

Simple. Because there is already evidence to support this claim. Some countries and states are using this strategy and either are starting to see or have already seen excellent results. For example, both Taiwan (which took a huge hit during the SARS outbreak of 2004) and South Korea (plagued by the MERS outbreak in 2015) learned from their past experience and launched a rapid response to the initial outbreaks of COVID-19. Both countries implemented all four of the "box it in" strategies discussed above within three weeks of the first cases appearing.

Additionally, in the US, many states, including California, Massachusetts, Illinois, and New York. are beginning to partner with local universities, hospitals, businesses, and non-profit organizations to lead the charge on contact tracing. While this task is much more complicated when the number of cases is still quite large, as is the case in the United States, signs are that these initiatives will have an impact. California Governor Gavin Newsom plans to build an “army of tracers” by the end of the month and calls this one of the most crucial steps to safely reopen California’s economy. Also, at the federal level, Senator Elizabeth Warren (MA) and Congressman Andy Levin (MI) have released the first proposal for a federal contact-tracing program to be included in the next emergency relief stimulus package. Even Google and Apple are teaming up to develop contact-tracing software. So expect to hear much more about contact tracing in the months to come as it will undoubtedly become a key component of restarting economies all throughout the world.

NCSE Director of Teacher Support Lin Andrews
Short Bio

Lin Andrews is NCSE Director of Eduation.