RESUMO
Background. Determining if a patient with SARS-CoV-2 remains infectious is an infection control challenge in healthcare settings;specially, among critically ill or profoundly immunosuppressed patients. We use an assay that detects minus-strand RNA as a surrogate for actively replicating SARS-CoV-2. We report positive strand-specific assays in relationship to time since admission and describe patients with a detectable strand-specific assay >20 days since admission. Methods. We use a 2-step rRT-PCR specific to the minus strand of the SARS-CoV-2 envelope gene. The strand-specific assay is used to evaluate for infectivity in asymptomatic patients with a positive admission screening or pre-procedural test or if ongoing replication is suspected (critical illness or profound immunosuppression). We retrieved strand-specific test results for patients hospitalized at Stanford Healthcare during August 2020-March 2022. We describe clinical characteristics for patients with a detectable minus strand-specific test >20 days since admission. Results. A total of 774 strand-specific tests were collected from 624 hospitalized patients. A total of 523 patients had only one test (84%) and 101 (16%) had >=2 tests. The test positivity rate varied by time since admission: 19% in tests performed 0-5 days, 28% in 6-10 days, 22% in 11-20 days, and 41% in those >20 days since admission. Among 35 patients tested >20 days since admission, 13 (37%) had >=1 detectable minus strand-specific test. Most were male (n=8, 62%) and mean age was 59. Of 13 patients with a detectable assay, seven (54%) had prolonged viral replication with persistent symptoms and detectable minus strand assays for >20 days from symptom onset. Of these seven patients, four had a transplant (3 lung, 1 liver), 1 ovarian cancer, 1 CAR-T cell therapy, and 1 ESRD without immunosuppression. The remaining eight patients with a detectable assay >20 days since admission had illness onset while hospitalized. Conclusion. Among hospitalized patients with SARS-CoV-2 infection, we found a varying positivity rate according to the timing of testing, possibly reflecting different indications for the test. The strand-specific assay may help assess for infectiousness in profoundly immunocompromised patients.
RESUMO
Background. Determining if a patient with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains infectious can be challenging in patients with severe disease or those profoundly immunosuppressed. We use an assay that detects minus-strand RNA as a surrogate for actively replicating SARS-CoV-2. Here, we describe a cohort of patients who had strand-assay reversion: a detectable minus strandspecific assay after having had an undetectable value which may signify relapse of infection or reinfection. Methods. We used a 2-step rRT-PCR specific to the minus strand of the SARS-CoV-2 envelope gene. The strand-specific assay is used to evaluate for infectivity in asymptomatic patients with a positive screening admission or pre-procedural test or in cases when ongoing infection was suspected (critical illness or profound immunosuppression). We collected minus strand-specific assays performed at Stanford Healthcare during August 2020-April 2022. We describe basic demographics and clinical characteristics for patients who reverted from undetectable to detectable using the minus strand-specific assay. Results. A total of 2,505 strand-specific tests were collected from August 2020-April 2022 from 2,064 patients. A total of 292 (14%) had two or more strandspecific tests. Of them, 19 (7%) had an undetected minus strand-specific assay followed by a subsequent detectable value. Of them, seven (37%) had a minus strandspecific CT value of < 33.Most were male (n=4), median age was 54 (range: 8-62). All were profoundly immunosuppressed: Four had hematologic malignancies and three were post transplantation (kidney, lung, bone marrow). Median time from onset of symptoms or first positive test to reversion was 41 days (range:27-159). Median time from undetectable to detectable minus strand specific test was 26 days (range:4-34). All cases were considered relapses or ongoing infection rather than a new infection. Conclusion. Among patients with SARS-CoV-2 infection and consecutive strand-specific testing, a small proportion reverted from negative to positive. Most were profoundly immunosuppressed. The strand-specific assay can be an important tool in the evaluation of suspected cases of relapse or reinfection.