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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 2

Characteristics of patients with toxic shock syndrome by the causative strain of Streptococcus pyogenes, Japan, 2023–2024*

Characteristic No. (%) M113SNPs No. (%) with non-emm1 Crude RR (95% CI) Crude OR (95% CI) p value†
No. patients
 176
 449
Sex
M 94 (53.4) 273 (60.8) Referent Referent
F
 82 (46.6)
 176 (39.2)
 1.09 (0.98–1.21)
 1.35 (0.95–1.92)
 0.1040
Age group, y
0–24 12 (6.8) 17 (3.8) 1.03 (0.99–1.08) 1.86 (0.87–3.98) 0.1368
25–39 22 (12.5) 39 (8.7) 1.04 (0.98–1.11) 1.50 (0.86–2.61) 0.1768
40–54 37 (21.0) 83 (18.5) 1.03 (0.85–1.13) 1.17 (0.76–1.81) 0.4985
55–69 43 (24.4) 118 (26.3) 0.98 (1.88–1.08) 0.91 (0.61–1.36) 0.6847
70–84 48 (27.3) 134 (29.8) 0.96 (0.87–1.08) 0.88 (0.60–1.30) 0.5579
>85
 14 (8.0)
 58 (12.9)
 0.85 (0.89–1.00)
 0.58 (0.32–1.07)
 0.0944
Deaths
All ages 55 (31.3) 104 (23.2) 1.12 (1.00–1.25) 1.51 (1.02–2.22) 0.0412
0–24 0 (0) 1 (5.9) 0.94 (0.84–1.06) 0 1.0000
25–39 8 (36.4) 4 (10.3) 1.41 (1.01–1.97) 5.00 (1.29–19.3) 0.0202
40–54 4 (10.8) 19 (22.9) 0.86 (0.74–1.02) 0.41 (0.13–1.30) 0.1395
55–69 13 (30.2) 22 (18.6) 1.17 (0.94–1.44) 1.89 (0.85–4.20) 0.1326
70–84 23 (47.9) 39 (29.1) 1.36 (1.01–1.82) 2.24 (1.14–4.41) 0.0217
>85 7 (50.0) 19 (32.8) 1.34 (0.77–2.33) 2.05 (0.63–6.70) 0.3525

*RR and OR between M113SNPs and non-emm1 are derived from univariate logistic regression analysis. OR and p values are unadjusted and should be interpreted with caution because they do not account for potential confounding factors such as underlying comorbidities, disease severity, or differences in initial treatment. OR, odds ratio; RR, risk ratio. †By Fisher exact test.

Main Article

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

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