Two Alternatives To The 14-Day Quarantine Period
The CDC still recommends a quarantine period of 14 days "to completely reduce the risk of spread of COVID-19" because a small percentage of infected people do not develop symptoms until 12 to 14 days post-infection. However, because most people who become symptomatic develop symptoms after four to five days, the CDC now approves of two alternatives to the 14-day quarantine period that provide, according to the CDC, an acceptable risk level of missing infectious cases:
- Quarantine can end after Day 10 without testing and if no symptoms have been reported during daily monitoring.
- With this strategy, residual post-quarantine transmission risk is estimated to be about 1% with an upper limit of about 10%.
- When diagnostic testing resources are sufficient and available, quarantine can end after Day 7 if a diagnostic specimen tests negative and if no symptoms were reported during daily monitoring. The specimen may be collected and tested within 48 hours before the time of planned quarantine discontinuation (e.g., in anticipation of testing delays), but quarantine cannot be discontinued earlier than after Day 7. Either a PCR test or rapid antigen diagnostic test is acceptable for ending quarantine early.
- With this "test-based" early discontinuation strategy, the residual post-quarantine transmission risk is estimated to be about 5% with an upper limit of about 12%.
In both cases, additional criteria (e.g., continued symptom monitoring and masking through Day 14) must be met and are outlined in the CDC guidance linked above. The test-based early discontinuation method should be used only if it will have no impact on the availability of diagnostic testing in the community.
The CDC issued these new alternatives in recognition of the physical, mental and economic hardships imposed by 14-day quarantines and to encourage greater quarantine compliance (recognizing that individuals are more likely to quarantine for seven days than 14).
New Guidelines Do Not Apply To Certain Individuals
The new recommendations do not apply to individuals who develop symptoms post-exposure or who test positive. Such individuals must continue to isolate ("quarantine" applies to people who are well but who may become ill, while "isolation" applies to those known to be ill) according to current CDC guidance: in most cases, for 10 days after the onset of symptoms and symptoms are improving and at least 24 hours fever-free without the use of fever reducing medications. The CDC does not currently recommend a test-based strategy for ending isolation for symptomatic or positive individuals, in large part because persons with COVID-19 will continue to test positive long after they are no longer infectious.
The immediate impact of this change in the CDC recommendations will be limited. It will take some time for the state, county and city health departments to incorporate the new CDC guidance into their orders and protocols, and many of those orders still require employers to impose a 14-day quarantine on suspected exposures. Some jurisdictions also may choose not to incorporate the new CDC guidance given the small but still significant risk of post-quarantine transmission noted above. In particular, the CDC estimates 20% to 40% of infected persons never develop symptoms but can still transmit the virus, with quarantine being the only effective countermeasure.
Employers also may choose to continue to require a 14-day quarantine, as the CDC guidance makes clear that 14 days is the gold standard. However, the new guidance gives employers options for getting critical workers who may have been exposed back to work earlier than before. Employers who choose to follow the new CDC guidance where permitted should adjust their employee screening certifications on travel and suspected exposures to account for the new time frames.
Finally, the CDC notes that antibody tests have not been approved as a way of excluding persons from quarantine, but other CDC guidance states that persons who have tested positive for COVID-19 in the three months before a new exposure may not need to quarantine again.
The CDC also released new guidance on post-travel quarantine with similar recommendations for early discontinuation through testing both pre and post-travel here.
Options to Reduce Quarantine for Contacts of Persons with SARS-CoV-2 Infection Using Symptom Monitoring and Diagnostic Testing