CDC Expands Definition of ‘Close Contact’ to Include Multiple Short Interactions

October 22, 2020

The US Centers for Disease Control and Prevention has expanded its definition of “close contact” to include individuals who spend 15 cumulative minutes within six feet of an individual infected with coronavirus (COVID-19) over a 24-hour period.

The new definition marks a significant expansion from prior Centers for Disease Control and Prevention (CDC) guidance, which had defined “close contact” to include only those individuals who spent 15 consecutive minutes within six feet of an infected individual. This deceptively subtle change could have a significant impact on how businesses identify who has been exposed to COVID-19 and who, therefore, should quarantine for 14 days. Indeed, after someone in the workplace tests positive, substantially more employees will likely be identified as close contacts and required to quarantine under the CDC’s updated guidance.

To mitigate this effect, employers may have to consider changes to workplace policies and operations in order to limit the number of workers who may need to be quarantined after an exposure.

Updated CDC Guidance

As of October 21, 2020, the definition section of the CDC’s Contact Tracing Guidance now states that a “close contact” is the following:

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 2 days before illness onset (or, for asymptomatic patients, two days prior to test specimen collection) until the time the patient is isolated. (Emphasis added.)

The CDC acknowledges that “[d]ata are limited, making it difficult to precisely define ‘close contact.’” Still, the CDC guidance now adds together the duration of each individual exposure that a person has over a 24-hour period to hit the 15-minute threshold. For example, someone would meet this revised definition if they had three separate five-minute exposures in a day, or even five separate three-minute exposures in a day.

The CDC also notes other important factors in defining a “close contact,” including proximity; the duration of exposure; whether the infected individual has symptoms; whether the infected person was likely to generate respiratory aerosols (e.g., was coughing, singing, shouting); and other environmental factors (e.g., crowding, adequacy of ventilation, whether exposure was indoors or outdoors).

The same day that the CDC announced its expanded definition of “close contact,” it also published a study detailing the likely circumstances in which a 20-year-old correctional officer in Vermont contracted COVID-19 after multiple brief encounters (approximately one minute each) with prison inmates. Although each encounter was significantly less than 15 minutes long, the officer nonetheless tested positive for COVID-19.

Key Takeaways

Following the CDC’s expanded definition of close contact, businesses should consider reexamining their social distancing protocols and contact tracing policies. Inevitably, under the new guidance, more individuals will be deemed to be close contacts in the event of a positive diagnosis. The CDC recommends that asymptomatic close contacts quarantine for 14 days from the date of their last known exposure to an infected individual, even if the close contacts test negative for COVID-19 or feel healthy, because symptoms may appear 2–14 days after exposure. Combining this 14-day quarantine recommendation with the new expanded definition of close contact may result in larger groups of employees, potentially entire teams, being required to quarantine. This result can create unexpected business hardship.

Although it is not mandatory for businesses to conform their policies to the CDC guidelines, the CDC guidance is a useful reference point to consider when crafting COVID-19 prevention practices and contact tracing procedures. Following the CDC guidance can help businesses with messaging to employees that the business is following applicable COVID-19 guidance. Additionally, it may assist businesses in limiting traditional tort liability and attempting to satisfy the General Duty Clause of the Occupational Safety and Health Act of 1970.

In light of the new CDC guidance, businesses should consider doing the following:

  • Incorporate the new definition of “close contact” into contact tracing protocols and make decisions about who should quarantine after an exposure based on the new definition.
  • Review social distancing policies to try and minimize opportunities for brief but repeated contact with other people in the workplace.
  • Divide the workforce into rotating teams so that only members of one team would need to quarantine after an exposure, thus reducing the potential impact on the business.
  • Enforce stricter physical distancing requirements and limitations on in-person meetings/gatherings to minimize potential cumulative close contact throughout the workday.
  • Evaluate the need for and feasibility of using technology (e.g., GPS monitoring apps, wearable devices such as a bracelet or badge, security videos) to help track the numerous short interactions that employees may have with others throughout the day.
  • Monitor state and local laws, regulations, and guidance for revisions in light of the CDC’s expanded definition of “close contact.” Public health agencies will likely be using the new guidance as they conduct their own contact tracing and impose requirements on who should quarantine.


If you have any questions or would like more information on the issues discussed in this LawFlash, please contact any of the following Morgan Lewis lawyers:

Washington, DC
Sharon Masling
Jonathan Snare
Kaiser Chowdhry
Alana Genderson
Jocelyn Cuttino

New York
Daniel Kadish