Can Contact Tracing Work Here?

One of the disappointments in our pandemic response has been the limited ability of our contact tracing—one of the fundamental activities of public health during an infectious disease outbreak—to control Covid-19 transmission. Hong Kong and Singapore initially contained their outbreaks by deploying thousands of public health workers to track down every person with a newly positive test, figure out whom they had been in contact with, and quickly get those people to quarantine. The United States did not. Which raises the question: have we now learned something about how to better perform this ancient public health function to make us confident that we could do better the next time around?

The US public health system faced three challenges in its attempt to make contact tracing work. First, we had inadequate Covid-19 testing early on: we could not identify all positive cases. The testing system failed—long waits to get tests and then more waiting for results. Without being able to readily identify and test those who have been in contact with an infected person, the chain of infection continued. By the time testing was readily available, rapid, and mostly free, the number of people infected far outstripped the supply of contact tracers.

Even if we had accurate testing available soon after Covid-19 was identified, workforce limitations was our second problem. Four months into the pandemic, in May 2020, we had only a fraction of the public health workers needed to launch an effective national contact tracing effort. At that time—with only 30,000 persons having tested positive—public health experts told Congress the country needed to increase the number of contact tracing staff tenfold to 100,000 or more. Yet even in December 2020, at the peak of US case load, there were still only 70,000 contact tracers nationwide.  Widespread community transmission across the country occurred within a few months of Covid-19’s arrival; it is unclear that any number of contact tracers could have kept up. The numbers grew too big too fast.

The third challenge was the lack of trust in public health authorities and services. As reported in a CDC analysis of 14 contact tracing programs from June to October 2020,  “no contacts were reported for two-thirds of persons with laboratory confirmed COVID-19 because they were either not reached for an interview or were interviewed and named no contacts.” In other words, citizens would not speak to contact tracing personnel.

We have learned that when the next pandemic arrives, even if we quickly create a test to identify cases, we may not be adequately prepared to perform the contact tracing necessary to control a new infection. We are not Hong Kong or Singapore, small islands with small populations. Our market economy disincentivizes inefficiency; we are unlikely to keep a workforce of already-trained contact tracers waiting around for the next infectious disease to come along, so once again we will face workforce training issues. And, complicating matters, distrust of government has only grown stronger during this pandemic making it likely harder—not easier—that a national contact tracing effort would be met by public consent. Economic and cultural forces worked against the best public health efforts with Covid-19, and only the reconsideration of all three challenges together will position us better the next time. Is that even realistic?  Or should we accept that a country of this size, this heterogeneity, is unlikely to be able to contain a full scale national pandemic and may more fruitfully use its resources on other approaches to mitigate the next epidemic?


Michael Stein & Sandro Galea

As we re-emerge from the pandemic, 2021 stands to be a turning point year for public health. In The Turning Point’s weekly essays, we reflect on what we learned during 2020, and what we are learning during 2021, that can guide us to the creation of a better, healthier world.

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