Reported Tuberculosis in the United States, 2020

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Table 25. Tuberculosis Cases and Clusters, by Cluster Size: United States, 2018–2020

See Surveillance Slide #68

Table 25. Tuberculosis Cases and Clusters, by Cluster Size: United States, 2017-2019
Cluster Size Clusters1 Cases2
n (%)3 n (%)4
Total 1,280 (100.0) 3,687 (100.0)
2-case cluster 860 (67.2) 1,720 (46.7)
3-case cluster 215 (16.8) 645 (17.5)
4-case cluster 85 (6.6) 340 (9.2)
5-case cluster 41 (3.2) 205 (5.6)
6-case cluster 22 (1.7) 132 (3.6)
7-case cluster 11 (0.9) 77 (2.1)
8-case cluster 11 (0.9) 88 (2.4)
9-case cluster 8 (0.6) 72 (2.0)
≥10 case cluster 27 (2.1) 408 (11.1)

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1Clusters have two or more cases with matching spoligotype and 24-locus mycobacterial interspersed repetitive unit-variable number tandem repeat type (GENType) within a county during the specified 3-year time period.

2Cases with matching spoligotype and 24-locus mycobacterial interspersed repetitive unit-variable number tandem repeat type (GENType) are members of a cluster within a county during the specified 3-year time period.

3Denominator is total number of clusters

4Denominator is total number of cases