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. 2022 Apr 30;4(2):133-136.
doi: 10.35772/ghm.2021.01124.

The first eleven cases of SARS-CoV-2 Omicron variant infection in Japan: A focus on viral dynamics

Nobumasa Okumura  1 , Shinya Tsuzuki  1   2   3 , Sho Saito  1 , Tomoya Saito  4 , Satoshi Takasago  5 , Masayuki Hojo  6 , Noriko Iwamoto  1 , Norio Ohmagari  1   2
Affiliations

The first eleven cases of SARS-CoV-2 Omicron variant infection in Japan: A focus on viral dynamics

Nobumasa Okumura et al. Glob Health Med. .

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant has spread rapidly worldwide. We report the clinical characteristics and threshold cycle (Ct) values of the first 11 patients infected with the SARS-CoV-2 Omicron variant in Japan. All patients were younger returnees from abroad; 10 patients had received two doses of vaccine. Estimated Ct values for the 11 patients were 6.0 (95% confidence interval [CI] 4.2-7.3) days for > 30, 10.6 (95% CI 9.5-11.9) days for > 35, 15.1 (95% CI 13.6-17.6) days for > 40, and 19.7 (95% CI 17.3- 23.7) days for > 45. Our results provide important insights for indicators of infection control.

Keywords: B.1.1.529; COVID-19; characteristics; threshold cycle.

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Conflict of interest statement

The authors have no conflicts of interest to disclose.

Figures

Figure 1.
Figure 1.
Detection of SARS-CoV-2 by RT-PCR targeting the nucleocapsid N2 gene. SARS-CoV-2: severe acute respiratory syndrome coronavirus 2; RT-PCR: reverse transcription polymerase chain reaction; UDL: under detection limit; ID: identification. Shaded area represents 95% confidence interval of the predicted value of the liner model. Threshold cycle values > 45 were regarded as 45 because of the detection sensitivity limit. Threshold cycle values were measured for the nucleocapsid N2 gene using Xpert® Xpress SARS-CoV-2.
See this image and copyright information in PMC

References

    1. World Health Organization. Classification of Omicron (B1. 1. 529): SARS-CoV-2 Variant of Concern. https://www.who.int/news/item/26-11-2021-classification-of-omicron-(b.1.... (accessed December 12, 2021).
    1. Global Initiative on Sharing Avian Influenza Data. Tracking of Variants. https://www.gisaid.org/hcov19-variants/ (accessed December 18, 2021).
    1. Ministry of Health, Labour and Welfare. Asymptomatic carriers of a SARS-CoV-2 infection (mutant variant) (Airport Quarantine) in Japan. November 30, 2021. https://www.mhlw.go.jp/stf/newpage_22507.html (accessed December 18, 2021). (in Japamese) .
    1. Cepheid. Xpert® Xpress SARS-CoV-2 Test: Package Insert, 2020. https://www.fda.gov/media/136315/download (accessed December 18, 2021).
    1. Blanquart F, Abad C, Ambroise J, Bernard M, Cosentino G, Giannoli JM, Débarre F. Characterisation of vaccine breakthrough infections of SARS-CoV-2 Delta and Alpha variants and within-host viral load dynamics in the community, France, June to July 2021. Euro Surveill. 2021; 26:2100824. - PMC - PubMed

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