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Disclaimer: Early release articles are not considered as final versions. Any changes will be reflected in the online version in the month the article is officially released.

Volume 32, Number 11—November 2026

Dispatch

Post–COVID-19 Expansion of Streptococcus pyogenes Lineages Causing Toxic Shock Syndrome, Japan, 2023–2024

Tadayoshi IkebeComments to Author , Hitoshi Otsuka, Mari Sasaki, Takahiro Yamaguchi, Yoshimi Date, Yu Kazawa, Kazuki Saito, Kaho Ikeda, Rumi Okuno, Yukihiro Akeda, and The Working Group for Beta-Hemolytic Streptococci in Japan1
Author affiliation: National Institute of Infectious Diseases, Tokyo, Japan (T. Ikebe, Y. Akeda); Yamaguchi Prefectural Institute of Public Health and Environment, Yamaguchi, Japan (H. Otsuka); Oita Prefectural Institute of Health and Environment, Oita, Japan (M. Sasaki); Osaka Institute of Public Health, Osaka, Japan (T. Yamaguchi); Kanagawa Prefectural Institute of Public Health, Kanagawa, Japan (Y. Date); Fukushima Prefectural Institute of Public Health, Fukushima, Japan (Y. Kazawa); Toyama Institute of Health, Toyama, Japan (K. Saito, K. Ikeda); Tokyo Metropolitan Institute of Public Health, Tokyo (R. Okuno)

Main Article

Table 1

Clinical outcomes by lineage in study of post–COVID-19 expansion of Streptococcus pyogenes causing toxic shock syndrome, Japan, 2023–2024*

Lineage No. cases Average age (IQR), y p value† No. (%) deaths p value†
M1UK 234 54.6 (41–69) <0.0001 48 (20.5) 0.4403
M113SNPs 176 58.5 (43–75) 0.0391 55 (31.3) 0.0412
M1global 60 58.9 (46–72) 0.1158 12 (20.0) 0.7431
Non-emm1 449 62.7 (50–78) Referent 104 (23.2) Referent

*IQR, interquartile range. †By Fisher exact test, significant at p<0.05 comparison with non-emm1. p values are unadjusted and should be interpreted with caution because they do not account for potential confounding factors such as underlying conditions, disease severity, or differences in initial treatment.

Main Article

1Additional members of this group who contributed data are listed at the end of this article.

Page created: September 08, 2026
Page updated: October 16, 2026
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