Duration of Isolation and Precautions for Adults with COVID-19

ATLANTA, GA-At this time, we do not know if someone can be re-infected with COVID-19. Data to date show that a person who has had and recovered from COVID-19 may have low levels of virus in their bodies for up to 3 months after diagnosis. This means that if the person who has recovered from COVID-19 is retested within 3 months of initial infection, they may continue to have a positive test result, even though they are not spreading COVID-19.

There are no confirmed reports to date of a person being reinfected with COVID-19 within 3 months of initial infection. However, additional research is ongoing. Therefore, if a person who has recovered from COVID-19 has new symptoms of COVID-19, the person may need an evaluation for reinfection, especially if the person has had close contact with someone infected with COVID-19. The person should isolate and contact a healthcare provider to be evaluated for other causes of their symptoms, and possibly retested.

CDC recommends that all people, whether or not they have had COVID-19, take steps to prevent getting and spreading COVID-19. Wash hands regularly, stay at least 6 feet away from others whenever possible, and wear masks.

Accumulating evidence supports ending isolation and precautions for persons with COVID-19 using a symptom-based strategy. This update incorporates recent evidence to inform the duration of isolation and precautions recommended to prevent transmission of SARS-CoV-2 to others, while limiting unnecessary prolonged isolation and unnecessary use of laboratory testing resources.

Available data indicate that persons with mild to moderate COVID-19 remain infectious no longer than 10 days after symptom onset. Persons with more severe to critical illness or severe immunocompromise likely remain infectious no longer than 20 days after symptom onset.  Recovered persons can continue to shed detectable SARS-CoV-2 RNA in upper respiratory specimens for up to 3 months after illness onset, albeit at concentrations considerably lower than during illness, in ranges where replication-competent virus has not been reliably recovered and infectiousness is unlikely. The etiology of this persistently detectable SARS-CoV-2 RNA has yet to be determined. Studies have not found evidence that clinically recovered persons with persistence of viral RNA have transmitted SARS-CoV-2 to others. These findings strengthen the justification for relying on a symptom based, rather than test-based strategy for ending isolation of these patients, so that persons who are by current evidence no longer infectious are not kept unnecessarily isolated and excluded from work or other responsibilities.

Reinfection with SARS-CoV-2 has not yet been definitively confirmed in any recovered persons to date. If, and if so when, persons can be reinfected with SARS-CoV-2 remains unknown and is a subject of investigation. Persons infected with related endemic human betacoronavirus appear to become susceptible again at around 90 days after onset of  infection. Thus, for persons recovered from SARS-CoV-2 infection, a positive PCR during the 90 days after illness onset more likely represents persistent shedding of viral RNA than reinfection.

• If such a person remains asymptomatic during this 90-day period, then any re-testing is unlikely to yield useful information, even if the person had close contact with an infected person.
• If such a person becomes symptomatic during this 90-day period and an evaluation fails to identify a diagnosis other than SARS-CoV-2 infection (e.g., influenza), then the person may warrant evaluation for SARS-CoV-2 reinfection in consultation with an infectious disease or infection control expert. Isolation may be warranted during this evaluation, particularly if symptoms developed after close contact with an infected person.

Correlates of immunity to SARS-CoV-2 infection have not been established. Specifically, the utility of serologic testing to establish the absence or presence of infection or reinfection remains undefined.

The recommendations below are based on the best information available in mid-July 2020 and reflect the realities of an evolving pandemic. Even for pathogens for which many years of data are available, it may not be possible to establish recommendations that ensure 100% of persons who are shedding replication-competent virus remain isolated. CDC will continue to closely monitor the evolving science for information that would warrant reconsideration of these recommendations.

Recommendations

1. Duration of isolation and precautions
   • For most persons with COVID-19 illness, isolation and precautions can generally be discontinued 10 days after symptom onset¹ and resolution of fever for at least 24 hours, without the use of fever-reducing medications, and with improvement of other symptoms.
     • A limited number of persons with severe illness may produce replication-competent virus beyond 10 days that may warrant extending duration of isolation and precautions for up to 20 days after symptom onset; consider consultation with infection control experts.
   • For persons who never develop symptoms, isolation and other precautions can be discontinued 10 days after the date of their first positive RT-PCR test for SARS-CoV-2 RNA.
2. Role of PCR testing² to discontinue isolation or precautions
   • For persons who are severely immunocompromised, a test-based strategy could be considered in consultation with infectious diseases experts.
   • For all others, a test-based strategy is no longer recommended except to discontinue isolation or precautions earlier than would occur under the strategy outlined in Part 1, above.
3. Role of PCR testing² after discontinuation of isolation or precautions
   • For persons previously diagnosed with symptomatic COVID-19 who remain asymptomatic after recovery, retesting is not recommended within 3 months after the date of symptom onset for the initial COVID-19 infection.
   • For persons who develop new symptoms consistent with COVID-19 during the 3 months after the date of initial symptom onset, if an alternative etiology cannot be identified by a provider, then the person may warrant retesting; consultation with infectious disease or infection control experts is recommended. Isolation may be considered during this evaluation based on consultation with an infection control expert, especially in the event symptoms develop within 14 days after close contact with an infected person.
   • For persons who never developed symptoms, the date of first positive RT-PCR test for SARS-CoV-2 RNA should be used in place of the date of symptom onset.
4. Role of serologic testing
   • Serologic testing should not be used to establish the presence or absence of SARS-CoV-2 infection or reinfection.

[1] Symptom onset is defined as the date on which symptoms first began, including non-respiratory symptoms.
[2] PCR testing is defined as the use of an RT-PCR assay to detect the presence of SARS-CoV-2 RNA..

Media Release/Center for Disease Control and Prevvention