The recommended isolation period for patients with confirmed Covid-19 infection is reduced from 14 to 10 days.
This recommendation is based on evidence that most patients with mild Covid-19 infection continue to shed SARS-CoV-2 nucleic acid from their upper airways for a median of approximately 7-12 days. Furthermore, the presence of detectable virus nucleic acid by RTPCR does not necessarily imply infectiousness. A better proxy for infectiousness is the ability to successfully culture the virus from a sample. In mild cases, cultures are generally only positive for 8-9 days after symptom onset.
The duration of infectiousness in patients with severe disease (i.e. requiring admission due to clinical instability) is less well established. In general, patients with severe disease may continue to shed virus at higher levels for longer periods than patients with mild disease. To provide a buffer, it is recommended that such patients be de-isolated 10 days after clinical stability has been achieved (e.g. after supplemental oxygen was discontinued), rather than 10 days after symptom onset.
Asymptomatic patients represent a conceptual challenge, since it is not possible to estimate where in the course of viral shedding they are at the time point at which they test positive. For simplicity, and to err on the side of caution, it is recommended that asymptomatic patients be isolated for 10 days following the date of their positive test.
Asymptomatic patient – De-isolate 10 days after testing
Mild disease – De-isolate 10 days after symptom onset
Severe disease – De-isolate 10 days after clinical stability achieved
The recommended isolation time is the period during which a patient is still considered infectious. This should be distinguished from the point at which a patient is medically well enough to return to work. Some patients, especially those who have had severe disease, may require to be booked off sick for longer than the above isolation periods.