J Korean Med Sci.  2022 Oct;37(39):e289. 10.3346/jkms.2022.37.e289.

Evaluation of In-Hospital Cluster of COVID-19 Associated With a Patient With Prolonged Viral Shedding Using Whole-Genome Sequencing

• Jung J
• Lee J
• Kim SK
• Park S
• Lim YJ
• Kim EO
• Park H
• Park MS
• Kim SH

• KMID: 2534027
• DOI: http://doi.org/10.3346/jkms.2022.37.e289

Abstract

Background
Patients with hematologic malignancies may produce replication-competent virus beyond 20 days of SARS-CoV-2 infection. However, data regarding the transmission of SARS-CoV-2 from patients with prolonged viral shedding is limited.
Methods
In May 2022, four additional cases of COVID-19 were reported in a hematologic ward at a tertiary care hospital in South Korea, after an 8-week isolation of a patient with prolonged viral shedding. We performed whole-genome sequencing (WGS) of SARS-CoV-2 to evaluate the possibility of post-isolation transmission from this prolonged viral shedding.
Results
A patient (case 1) with acute myeloid leukemia was released from isolation 54 days after the diagnosis of COVID-19 based on rising Ct value of up to 29.3, and moved to a sixpatient room. On days 10 and 11 post-isolation, his doctor (case 2) and 2 patients who were his roommates (case 3, 4) had positive SARS-CoV-2 PCR results. Additionally, 16 days postisolation, another patient (case 5) in a remote room had positive SARS-CoV-2 PCR result. All the three patients were hospitalized for ≥ 14 days when they were diagnosed with SARS-CoV-2 infection. Except for case 3, the remaining 4 cases were available for WGS, which revealed that case 1 exhibited a 7 nucleotides difference in comparison to cases 4 and 5 and case 2 displayed a 20 nucleotides difference compared with case 1, while sequences of cases 4 and 5 were identical.
Conclusions
Despite the possibility of transmission from the patient with prolonged viral shedding, no evidence of the transmission of SARS-CoV-2 from the patient with prolonged positive RT-PCR using WGS was found.

Keyword

SARS-CoV-2; COVID-19; Whole-Genome Sequencing; Hematologic Malignancy; Post-Isolation Transmission

Figure

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  Fig. 1 Ct value (E gene, case 1), diagnosis day and spatiotemporal relationship between cases.Ct = cycle threshold, HCW = healthcare worker, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2, PCR = polymerase chain reaction.

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  Fig. 2 Comparison of whole-genome sequences of the cases.

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