What are the implications of the CDC’s new ”Close contact” definition?
Last week, the CDC changed their definition of what it means to be a “close contact” to reflect a surprising case that was contracted in a Vermont correctional facility. Simply put, the definition changed such that you are now considered a “close contact” if you have been within 6 feet of an infected person for 15 minutes CUMULATIVELY in a 24 hour period rather than necessitating that the 15 minutes be CONSECUTIVE. The timing of exposure to the “infected person” includes being in close contact with them starting from 2 days before their symptom onset (or 2 days before testing) until the time the patient is isolated.
As mentioned, the revision was inspired by a case that occured in a correctional facility. A corrections officer interacted briefly with incarcerated individuals who were asymptomatic, but later found to be COVID-19 positive. In total, he spent 17 minutes within 6 feet of infected patients over his 8 hour shift. For the most part, he was wearing a mask, gown, goggles and gloves, and the infected people were wearing masks, but there were some brief unmasked exposures as well. He was not considered a close contact and thus continued to work, but 7 days later, he unfortunately developed COVID-19.
So, as cases increase at an alarming rate across the country and globally (the WHO reported a new record high for global weekly incidence for the sixth consecutive week), it’s important to take this new definition into account. Presumably the officer contracted the virus in one of the interactions where he wasn’t wearing a mask, so it’s a good reminder to wear a mask if you are going to be spending time near anyone that is not in your household. Per the CDC, there continue to be other factors to consider when defining close contact including “proximity (closer distance likely increases exposure risk), the duration of exposure (longer exposure time likely increases exposure risk), whether the infected individual has symptoms (the period around onset of symptoms is associated with the highest levels of viral shedding), if the infected person was likely to generate respiratory aerosols (e.g., was coughing, singing, shouting), and other environmental factors (crowding, adequacy of ventilation, whether exposure was indoors or outdoors).”
If at any time you do meet the criteria to be defined as a close contact, the safest thing to do is quarantine for 14 days. For information on testing after exposure, please see our FAQ “If I’ve been exposed, how soon should I be tested for COVID-19?”
Jackie Phillips, MD, October 27, 2020