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

Kimihito Ito; Chayada Piantham; Hiroshi Nishiura

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

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

Authors

Kimihito Ito¹, Chayada Piantham², Hiroshi Nishiura³

Affiliations

¹ International Institute for Zoonosis Control, Hokkaido University, Hokkaido, Japan.
² Graduate School of Infectious Diseases, Hokkaido University, Hokkaido, Japan.
³ Graduate School of Medicine, Kyoto University, Kyoto, Japan.

PMID: 34240695
PMCID: PMC8268651
DOI: 10.2807/1560-7917.ES.2021.26.27.2100570

Abstract

Using numbers of SARS-CoV-2 variants detected in Japan as at 13 June 2021, relative instantaneous reproduction numbers (R_RI) 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, R_RI 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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19*
Humans
Japan / epidemiology
SARS-CoV-2*
Tokyo