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Volume 31, Number 8—August 2025
Research
Group A Streptococcus among American Indian Persons, White Mountain Apache Tribal Lands, United States, 2016–20191
Table 2
Incidence rates of severe and invasive group A Streptococcus infection among American Indian persons in the White Mountain Apache Tribal lands, Arizona, USA, 2017–2019
Characteristic | Total no. | Severe and invasive infections |
Invasive infections |
Severe infections |
|||||
---|---|---|---|---|---|---|---|---|---|
No. | Incidence* (95% CI) | No. | Incidence* (95% CI) | No. | Incidence* (95% CI) | ||||
Overall | 34,061 | 161 | 472.7 (405.2–551.4) | 48 | 140.9 (106.2–187.0) | 113 | 331.8 (276.0–398.8) | ||
By age, y | |||||||||
0–4 | 3,391 | 7 | 206.4 (98.5–432.7) | 1 | 29.5 (4.2–209.4) | 6 | 176.9 (79.5–393.6) | ||
5–17 | 8,791 | 11 | 125.1 (69.3–225.9) | 0 | 0 | 11 | 125.1 (69.3–225.9) | ||
18–49 | 14,514 | 90 | 620.1 (504.7–761.9) | 22 | 151.6 (99.8–230.1) | 68 | 468.5 (369.6–593.9) | ||
50–64 | 4,845 | 32 | 660.5 (467.6–932.9) | 12 | 247.7 (140.8–435.9) | 20 | 412.8 (266.6–639.3) | ||
>65 |
2,520 |
21 |
833.3 (544.3–1,275.8) |
13 |
516.0 (300.0–887.3) |
8 |
317.5 (158.9–634.1) |
||
Year 1† | 16,948 | 79 | 466.1 (374.1–580.8) | 23 | 135.7 (90.2–204.2) | 56 | 330.4 (254.4–429.2) | ||
By age, y | |||||||||
0–4 | 1,693 | 5 | 295.3 (123.1–708.8) | 1 | 59.1 (8.3–419.3) | 4 | 236.3 (88.8–629.0) | ||
5–17 | 4,366 | 5 | 114.5 (47.7–275.0) | 0 | 0 | 5 | 114.5 (47.7–275.0) | ||
18–49 | 7,260 | 42 | 578.5 (427.9–782.1) | 8 | 110.2 (55.1–220.3) | 34 | 468.3 (334.9–654.9) | ||
50–64 | 2,383 | 14 | 587.5 (348.5–990.5) | 6 | 251.9 (113.3–560.0) | 8 | 335.7 (168.1–670.5) | ||
>65 |
1,246 |
13 |
1043.3 (607.5–1,791.8) |
8 |
642.1 (321.8–1,281.0) |
5 |
401.3 (167.3–962.4) |
||
Year 2† | 17,113 | 82 | 479.2 (386.1–594.7) | 25 | 146.1 (98.7–216.1) | 57 | 333.1 (257.0–431.6) | ||
By age, y | |||||||||
0–4 | 1,698 | 2 | 117.8 (29.5–470.8) | 0 | 0 | 2 | 117.8 (29.5–470.8) | ||
5–17 | 4,425 | 6 | 135.6 (61.0–301.7) | 0 | 0 | 6 | 135.6 (61.0–301.7) | ||
18–49 | 7,254 | 48 | 66.2 (499.1–877.2) | 14 | 193.0 (114.4–325.7) | 34 | 468.7 (335.2–655.5) | ||
50–64 | 2,462 | 18 | 731.1 (461.4–1,158.5) | 6 | 243.7 (109.5–541.9) | 12 | 487.4 (277.2–857.1) | ||
>65 | 1,274 | 8 | 627.9 (314.7–1,252.9) | 5 | 392.4 (163.6–941.3) | 3 | 235.5 (76.1–729.2) |
*Cases/100,000 persons. †No significant difference was observed between years 1 (Mar 2017–Feb 2018) and 2 (Mar 2018–Feb 2019) for all group A Streptococcus (incidence rate ratio: 1.03; 95% confidence interval: 0.76–1.40), invasive group A Streptococcus (incidence rate ratio: 1.08; 95% confidence interval: 0.61–1.90) or severe group A Streptococcus (incidence rate ratio: 1.01; 95% confidence interval: 0.70–1.46).
1Preliminary results from this study were presented at IDWeek, October 2–6, 2019, Washington, DC, USA
2These first authors contributed equally to this article.
3These senior authors contributed equally to this article.