Outbreak Testing: Who to Test and What are the Parameters?

Posted on September 30, 2021 by Kari Everson

Top of mind for many members is the CDC guidance regarding testing during an outbreak. When a new facility onset case of COVID-19 is found in a staff member or resident, the organization must proceed with outbreak testing. So how do we know who to test and what are the testing parameters? The information below may give you the answers you need.

Contact Tracing
If the organization is capable and able to complete contact tracing within 24 hours of the known new facility onset case, testing may occur for only residents who had close contact with the positive individual or staff who experienced a high-risk exposure. For those who had close contact or a high-risk exposure to someone positive for COVID-19, testing should be completed approximately two days after the exposure and again between days five through seven after the exposure.  The day of exposure is day zero. No further outbreak testing is required if no new cases are identified on either day two or during testing on days five through seven. If a new case of COVID-19 is identified during testing, contact tracing must be completed for the newly positive individual, and testing must continue for those who had close contact or a high-risk exposure to the newly diagnosed individual.

Broad Outbreak Testing Strategy
A broader outbreak testing strategy should be used if the organization cannot complete contact tracing in 24 hours or cannot adequately complete contact tracing. There are two options. First, the entire unit or area where the new onset case lives or worked can be tested, or there can be whole-house testing. Whichever is chosen, testing should be completed on approximately day two and again on days five through seven. If NO new facility onset cases are identified on day two, and no new facility onset cases are identified on days five through seven, outbreak testing is complete. If new positive cases are identified, outbreak testing must continue.  Other instances where an organization should consider a broader testing strategy include instances when:

• the organization does not have the expertise, resources, or ability to identify all close contacts / high-risk exposures
• you cannot identify all potential exposures or the number of exposures are too numerous to manage;
• contact tracing testing response fails to halt transmission; or
• the public health authority directs you to do so.

There is a question about whether "immediate" testing should be done as soon as possible or not before day two after exposure. It is easiest to think about in terms of symptoms v. no symptoms. If a resident or employee has COVID-19 symptoms, they should be tested immediately, as soon as possible. If someone experienced a high-risk exposure or exposure via close contact and is not symptomatic, they should be tested as soon as possible but not sooner than two days after exposure. This is because the test is far less likely to yield a positive result during the first two days as the virus is still incubating. If that person becomes symptomatic before day two, testing is a good idea. If not, wait until day two and start the testing process then.

What About Quarantine?
Testing guidance should not be confused with quarantine guidance. Many ask about testing if the staff and/or resident were wearing appropriate PPE. Whether or not someone was wearing appropriate PPE, the individuals should be tested if they meet the definition of close-contact exposure or high-risk exposure.  Unvaccinated residents should be quarantined, even if testing is negative, and cared for by a health care worker using the appropriate PPE for someone in transmission-based precautions.  These residents should not participate in activities during the testing time period.

Fully vaccinated residents should test, but they do not require quarantine in their rooms.  Staff who care for them do not need to wear PPE consistent with transmission-based precautions; they should continue to wear source control masks and eye protection.  In the event of ongoing transmission, strong consideration should be given to quarantining fully vaccinated residents.

You can find testing processes in the CDC guidance and CMS memo QSO-20-38. Assisted living testing guidance is being finalized and should be published by MDH early this week. The guidance will come out via a compendium email. If you have questions about outbreak testing, timing, or frequency, please contact Kari Everson.