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CDC Expands 'Close Contact' Definition of COVID-19 Patients

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Key Takeaways

  • The CDC expanded its definition of “close contact” to include people who have been within 6 feet of a person with COVID-19 for a cumulative total—including many short periods of exposure—of 15 minutes or more in a 24-hour period. 
  • The definition of “close contact” was previously limited to exposure within 6 feet of a person with COVID-19 for one period of 15 minutes or more in a 24-hour period.
  • This redefined definition will likely affect contact tracing, which will become more difficult for health officials for infected people who are in contact with multiple people for short periods of time throughout the day.

The Centers for Disease Control and Prevention (CDC) announced on October 21 that it has expanded its definition of who is considered a “close contact” of a person with coronavirus.

“Previously, the CDC defined a close contact as someone who spent 15 minutes or more within six feet of someone contagious with COVID-19,” Leann Poston, MD, MBD, MEd, a physician with Invigor Medical, a men's health clinic based in Washington State, tells Verywell. “This was an arbitrary definition that was put in place to have a benchmark to work with when contact tracing.”

But the CDC updated its guidance after reviewing footage of a corrections officer in Vermont who came in contact with an infected inmate over multiple short periods of time but was never in prolonged contract with the inmate, according to the report. The corrections officer later contracted COVID-19.

“The correctional officer reported no other known close contact exposures to persons with COVID-19 outside work and no travel outside Vermont during the 14 days preceding illness onset,” the CDC’s report noted.

The updated guidance now defines close contact as “someone who was within 6 feet of an infected person for a cumulative total of 15 minutes or more over a 24-hour period, starting from two days before illness onset (or, for asymptomatic patients, two days prior to test specimen collection) until the time the patient is isolated,” according to the CDC’s website.

Why the Change?

The CDC’s report highlights the need for health professionals to consider each contact a person with COVID-19 may have had with people while they were infected, Poston says. 

"Since the aggregate of many small interactions over a 24-hour period has been found to be enough for the virus to spread, exposure notification models and contact tracing protocols need to be adjusted,” says Micha Benoliel, co-founder of Coalition Network Foundation, a non-profit that promotes free, open-source solutions to combat the spread of COVID-19. “Each short interaction is now important to tabulate in 24-hour aggregate cycles to get a full picture in the process of contact tracing and exposure notification," he tells Verywell.

A few things that haven’t changed? The continued importance of mask-wearing, social distancing, and regular hand-washing, especially while researchers continue to work to better understand COVID-19 and the methods by which it is spread.

Leann Poston, MD

This change is going to make contact tracing more difficult, especially for employees who might be in contact with multiple people for short periods of time during the day.

— Leann Poston, MD

What This Means for Contact Tracing

For starters, what is contact tracing anyway? Put simply, contact tracing is a process used by health departments to, you guessed it, trace the origins of a COVID-19 infection.

Contact tracers work with communicable disease patients to get in touch with anyone they may have been in contact with, recommending isolation and quarantine when necessary.

The CDC's expanded definition of “close contact" could make contact tracing tricky, Poston says. 

“This change is going to make contact tracing more difficult especially for employees who might be in contact with multiple people for short periods of time during the day,” she says, adding that this includes people who work in schools, prisons, or retail businesses.

What This Means For You

Health professionals are working hard to understand coronavirus, but still have a lot of unanswered questions about the disease. In the meantime, that means continued adherence to safety precautions like mask-wearing, maintaining social distance, regular hand-washing, and avoiding large gatherings, especially indoors.

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  1. Centers for Disease Control & Prevention. Public health guidance for community-related exposure. Updated October 21, 2020.

  2. Pringle JC. Covid-19 in a correctional facility employee following multiple brief exposures to persons with covid-19 — vermont, july–august 2020MMWR Morb Mortal Wkly Rep. 2020;69.

  3. Centers for Disease Control and Prevention. Coronavirus disease 2019 (COVID-19). Updated October 21, 2020.