Contributed by Suzannah Wilson Overholt, July 1, 2020
As has come to be expected, the guidance regarding COVID-19 has changed again. This time the CDC narrowed the definition of who constitutes a “close contact” for purposes of tracing people with potential exposure to someone who has COVID-19.
While a “close contact” is still defined as someone who was within 6 feet of an infected person for at least 15 minutes, what has changed is when the exposure occurred during the ill person’s sickness. The relevant time is now from two days before illness onset (or, for asymptomatic patients, two days prior to specimen collection) until the time the patient is isolated.
Before this change, the relevant period was from two days before symptom onset until the ill person met the criteria for discontinuing home isolation, which requires the person to be symptom free for at least three days and for at least 10 days to pass from symptom onset or, if someone is being tested, to be symptom free for three days and to have two negative tests at least 24 hours apart.
The new definition effectively reduces the time frame for identifying close contacts to as little as a few days – two days before the symptoms started to the start of home isolation could occur in three days. This change should be helpful to anyone who is faced with the task of identifying close contacts of individuals with COVID-19 – including employers, contact tracers, and public health officials. Their jobs just got a bit easier since there is now a smaller field of contacts to consider. The guidance also makes sense since, presumably, the ill person should not have any contacts (outside household members) once home isolation begins.
The CDC’s guidance continues to remind us that the 15 minute standard is not necessarily a rigid test. Factors to consider include proximity, the duration of exposure (e.g., longer exposure time likely increases exposure risk), whether the individual has symptoms (e.g., coughing likely increases exposure risk) and whether either the ill person or contact was wearing an N95 respirator (which reduces the risk of exposure). Note that using a fabric face covering should not be considered as reducing risk.
Different criteria apply in healthcare settings, where a prolonged exposure is defined as any exposure greater than 15 minutes because the contact is someone who is ill. While the CDC recognizes that brief interactions are less likely to result in transmission, symptoms and the type of interaction (e.g., did the person cough directly into the face of the individual) are important.
Employers must still be vigilant about identifying close contacts of any employees who have COVID-19. If you have not established an internal policy for doing so, now is the time.