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

Jiwon Jung, Jungmin Lee, Sun Kyung Kim, Soyeon Park, Young Ju Lim, Eun Ok Kim, Heedo Park, Man Seong Park, Sung Han Kim

Research output: Contribution to journalArticlepeer-review


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 six-patient 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 post-isolation, 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.

Original languageEnglish
Pages (from-to)e289
JournalJournal of Korean medical science
Issue number39
Publication statusPublished - 2022 Oct 10


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

ASJC Scopus subject areas

  • Medicine(all)


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