CDC Scales Back Contact Tracing Recommendations to Focus on High-Risk Settings and Groups

Widely-available vaccines and decreasing case numbers influenced the change in guidance.

Image of a hand with scissors cutting a COVID-19 contact tracing diagram, showing covid cases connected by red lines
Getty / Jo Imperio

Contact tracing—the public health tool meant to manage the spread of COVID-19—is no longer universally recommended to track and contain the coronavirus, the Centers for Disease Control and Prevention (CDC) said earlier this week. Now, the agency plans to only recommend the tool in high-risk settings and groups.

The CDC quietly made the recommendation on February 28, when it updated its online page dedicated to case investigation and contact tracing. The new guidance veers away from the original goal of both tools—to investigate and contact trace every case of COVID-19—initiated at the beginning of the pandemic. When it was introduced, the CDC estimated the US would need about 100,000 contact tracers to manage the virus.

It's not just the CDC making these new recommendations for contact tracing, either: New York City will also end its contact tracing program in April, as reported by The New York Times. And some states—including Maine, Vermont, and Massachusetts—have suspended or shifted the focus of their programs to focus on higher risk communities, according to the National Academy for State Health Policy.

The suspension of universal contact tracing and case investigation doesn't mean that the practices are going away completely—just that the strategy is being refined, due to a variety of factors, like declining cases, vaccine availability, and increased use of self-tests. Here's what you need to know about why the CDC made this decision—and how it will instead begin focusing its efforts.

How Contact Tracing Worked in the US

Contact tracing is a public health tool that's been used for decades by state and local health departments to help stop or slow the spread of infectious diseases, according to the CDC. "Contact tracing is a program that has a long and storied history of identifying the spread of infectious agents," Perry N. Halkitis, PhD, MPH, dean of the Rutgers School of Public Health, told Health. "It works particularly well when there's not an overabundance of infections being spread at extremely quick rates."

In the case of COVID-19, contact tracing let people know if they may have been exposed to the virus and if they should monitor themselves for symptoms of the virus, the CDC says. It also helped people who may have been exposed to the virus get tested and asked them to self-isolate or self-quarantine.

But contact tracing quickly came under fire in the U.S. as contact tracers struggled to keep up with the rapid spread of COVID-19 across the country. "Contact tracing in the United States was never robust because public health agencies have chronically been under-resourced," infectious disease expert Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, told Health. "We were really unable to develop a case investigation and contact tracing workforce that could keep up with cases."

As COVID-19 quickly spread across the country and become widespread in many areas, there were several reports of people hearing from contact tracers weeks after an exposure, Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York, told Health. At that point, he notes, someone would have already been infected, making contact tracing "useless."

"Most public health offices were overwhelmed," Dr. Russo said. "Contact tracing almost needs to be done in real time to be effective. Meaning, when you find out you have a positive test, you want individuals that were potentially exposed to be notified right away to quarantine and get tested. That didn't happen."

Overall, "contact tracing was not helpful," James McDeavitt, MD, executive vice president and dean of clinical affairs at Baylor College of Medicine, told Health. Among other things, Dr. McDeavitt points out that the incubation period of the virus has gotten shorter over time and that it's difficult to even get people to pick up their phones. "Our traditional way of contacting people through contact tracing is via telephone and nobody answer the telephone," he says.

Of course, this isn't placing blame on public health agencies—COVID-19's spread was just fast. "Because COVID-19 was spreading very rapidly, it was difficult for contact tracing to keep up," Halkitis said. "Ultimately, this disease and its continual change and proliferation made it very difficult for contact tracing to keep up with the spread of disease."

Moving Away From a Universal Approach

Generally speaking, universal contact tracing and case investigation is no longer necessary in this phase of the pandemic. "The updated guidance is in response to changes in the nature of the pandemic and the increasing availability of new tools to prevent transmission and mitigate illness," Kristen Nordlund, a CDC spokesperson, told Health.

Nordlund said the emergence (and dominance) of variants—many that have very short incubation periods and spread rapidly—helped initiate the change, as did "high levels of infection- or vaccine-induced immunity." The wide availability of safe and effective vaccines, and increased availability of at-home testing options (which allows people to quickly notify close contacts, and may not always be reported to health departments) were other deciding factors.

It seems people in the US had also lost interest in contact tracing programs: The CDC noted that decreased participation of people with COVID-19 and their contacts in these contact tracing situations and case investigations, led to the rollback too. Many people may not even be aware they have COVID-19, due to asymptomatic illness, which also makes contact tracing hard.

Basically: "We have a highly immune population and many tools to deal with COVID-19, so contact tracing has less of a role," Dr. Adalja said.

Focusing on High-Risk Settings and Groups

The CDC doesn't plan to do away with contact tracing and case investigations for COVID-19 entirely. Instead, the agency recommends public health departments prioritize specific settings and groups at increased risk of COVID-19 spread, like long-term care facilities, jails, and homeless shelters, along with "unusual clusters of cases" that may show up, Nordlund said. That's especially true for people in those settings who are unvaccinated or at risk of severe disease from COVID-19.

The CDC also recommends that public health agencies focus resources on things like public education to encourage people with COVID-19 to isolate and inform their close contacts that they may have been exposed. "It really works best when you shift that responsibility to the infected individual," Dr. Russo said. "That really speeds up the process."

Still, people should continue to do their best to protect themselves from COVID-19. "The biggest steps people can take to stay safe right now is to get vaccinated and boosted," Halkitis said. "And, if the CDC comes back and says we need to get another booster, to do it. It's the most effective tool we have now."

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

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