Table 2.

Proposed features for distinguishing SARS-CoV-2 reinfection from prolonged SARS-CoV-2 viral shedding

	SARS-CoV-2 reinfection	Prolonged SARS-CoV-2 viral shedding
Sequencing	Confirmed RNA sequencing with evidence of distinct SARS-CoV-2 viral strains at distinct episodes would provide a definitive diagnosis of SARS-CoV-2 reinfection	RNA sequencing showing the same SARS-CoV-2 viral strains at distinct periods could suggest prolonged SARS-CoV-2 viral shedding rather than reinfection; unless clinical suspicion is high for SARS-CoV-2 reinfection, further evaluation would be needed to assess if the patient has been reinfected with the same SARS-CoV-2 strain
Cycle threshold (Ct) values	Variability in SARS-CoV-2 Ct detection has been documented in cases of SARS-CoV-2 reinfection, with some cases with increased or decreased Ct values on reinfection episode (with Ct varying from 16.6 to 36.85)8	Likely to have high Ct values suggesting low level viral shedding; however, low Ct values may be observed in immunocompromised patients who have decreased ability to clear the virus
Viral culture	Likely to be positive	Could be positive or negative (latter representing non-viable virus detected via SARS-CoV-2 PCR tests)
Timing of repeat positive testing	Variable; time between positive SARS-CoV-2 RNA PCR in documented cases of SARS-CoV-2 reinfection ranges from 48 to 142 days8	Variable
Antibody testing in blood	Could be positive or negative*	Could be positive or negative
Host characteristics	Variable; the majority of documented cases of SARS-CoV-2 infections noted in immunocompetent hosts (with the exception of one patient taking inhaled corticosteroids)8	Variable; notably, immunocompromised hosts are more likely to have prolonged episodes of SARS-CoV-2 viral shedding
Symptomatic vs. asymptomatic presentation	Variable symptoms; may have milder (including asymptomatic presentations) or worsening symptoms as noted in prior cases of SARS-CoV-2 reinfection8	Predicted to have asymptomatic presentation if due to prolonged SARS-CoV-2 viral shedding

*SARS-CoV-2 re-infections may occur more commonly in individuals with waning immunity after their first SARS-CoV-2 infection.