The symptom-based, time-based, and test-based strategies may result in different timeframes for discontinuation of isolation post-recovery. For all scenarios outlined above, the decision to discontinue isolation should be made in the context of local circumstances.
Note that recommendations for discontinuing isolation in persons known to be infected with COVID-19 could, in some circumstances, appear to conflict with recommendations on when to discontinue quarantine for persons known to have been exposed to COVID-19. CDC recommends 14 days of quarantine after exposure based on the time it takes to develop illness if infected. Thus, it is possible that a person known to be infected could leave isolation earlier than a person who is quarantined because of the possibility they are infected.
This recommendation will prevent most, but cannot prevent all, instances of secondary spread. The risk of transmission after recovery is likely substantially less than that during illness; recovered persons will not be shedding large amounts of virus by this point, if they are shedding at all. Employers and local public health authorities can choose to apply more stringent criteria for certain persons where a higher threshold to prevent transmission is warranted.
For certain populations, a longer timeframe after recovery may be desired to minimize the chance of prolonged shedding of replication-competent virus. Such persons include:
Experience from other respiratory viral infections, in particular influenza, suggests that people with COVID-19 may shed detectable viral materials of unknown infectious potential for an extended period of time after recovery. The best available evidence suggests that most persons recovered from illness with detectable viral RNA (either persistent or recurrent) are likely no longer infectious, but conclusive evidence is not currently available. Prolonged viral shedding has been demonstrated without direct correlation with replication competent virus. Although persons may produce PCR-positive specimens for up to 6 weeks, it remains unknown whether these PCR-positive samples represent the presence of infectious virus. Such persons should consult with their healthcare provider; strategies to address this might include additional PCR testing. When a test-based strategy is not feasible or desired, consider consultation with local infectious disease experts about discontinuing home isolation for patients who might have prolonged viral shedding, including those who are immunocompromised.