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. 2021 Jul;26(27):2100570.
doi: 10.2807/1560-7917.ES.2021.26.27.2100570.

Predicted dominance of variant Delta of SARS-CoV-2 before Tokyo Olympic Games, Japan, July 2021

Kimihito Ito  1 , Chayada Piantham  2 , Hiroshi Nishiura  3
Affiliations

Predicted dominance of variant Delta of SARS-CoV-2 before Tokyo Olympic Games, Japan, July 2021

Kimihito Ito et al. Euro Surveill. 2021 Jul.

Abstract

Using numbers of SARS-CoV-2 variants detected in Japan as at 13 June 2021, relative instantaneous reproduction numbers (RRI) of the R.1, Alpha, and Delta variants with respect to other strains circulating in Japan were estimated at 1.25, 1.44, and 1.95. Depending on the assumed serial interval distributions, RRI varies from 1.20-1.32 for R.1, 1.34-1.58 for Alpha, and 1.70-2.30 for Delta. The frequency of Delta is expected to take over Alpha in Japan before 23 July 2021.

Keywords: Delta variant; RRI; SARS-CoV-2; Tokyo Olympic Games; relative instantaneous reproduction numbers.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1
Estimated temporal changes in SARS-CoV-2 variant relative frequencies of R.1, Alpha and Delta VOC and other strains circulating, Japan, 1 December 2020 to 11 September 2021
Figure 2
Figure 2
Temporal changes in the population average of the relative instantaneous reproduction numbers with respect to SARS-CoV-2 strains other than the R.1 variant or Alpha or Delta VOC, Japan, 1 December 2020 to 11 September 2021
See this image and copyright information in PMC

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