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Volume 32, Number 6—June 2026
Research
Characteristics of Plausible Source Cases Responsible for Recent Mycobacterium tuberculosis Transmission, United States, 2018–2022
Table 3
Characteristics of most likely plausible TB cases during 2018–2020 responsible for recent Mycobacterium tuberculosis transmission to >1 secondary TB cases during 2020–2022, United States*
| Characteristic | Nonplausible source | Plausible source for >1 TB cases |
p value† | |
|---|---|---|---|---|
| 1–2 cases | >3 cases | |||
| Total no. (%) cases, n = 19,577 |
18,932 (96.7) |
593 (3.0) |
52 (0.3) |
|
| Sex | <0.001 | |||
| M | 11,640 (61.5) | 415 (70.0) | 41 (78.9) | |
| F | 7,289 (38.5) | 178 (30.0) | 11 (21.1) | |
| Unknown |
3 (0.0) |
0 (0.0) |
0 (0.0) |
|
| Age, y | <0.001 | |||
| <5 | 189 (1.0) | 0 (0.0) | 0 (0.0) | |
| 5–14 | 198 (1.0) | 6 (1.0) | 0 (0.0) | |
| 15–24 | 1,828 (9.7) | 87 (14.7) | 7 (13.5) | |
| 25–44 | 5,620 (29.7) | 214 (36.1) | 25 (48.1) | |
| 45–64 | 5,597 (29.6) | 225 (37.9) | 18 (34.6) | |
| >65 |
5,504 (29.1) |
61 (10.3) |
2 (3.8) |
|
| Origin of birth | <0.001 | |||
| United States | 5,022 (26.5) | 306 (51.6) | 37 (71.2) | |
| Non-US country | 13,881 (73.3) | 286 (48.2) | 15 (28.8) | |
| Unknown |
29 (0.2) |
1 (0.2) |
0 (0.0) |
|
| Race and ethnicity‡ | <0.001 | |||
| Hispanic or Latino | 5,513 (29.1) | 227 (38.3) | 9 (17.3) | |
| American Indian/Alaska Native | 186 (1.0) | 15 (2.5) | 7 (13.5) | |
| Native Hawaiian/Pacific Islander | 221 (1.2) | 22 (3.7) | 1 (1.9) | |
| Black | 3,486 (18.4) | 188 (31.7) | 28 (53.8) | |
| Asian | 7,175 (37.9) | 68 (11.5) | 4 (7.7) | |
| White | 2,150 (11.4) | 66 (11.1) | 3 (5.8) | |
| Multiple race | 141 (0.7) | 2 (0.3) | 0 (0.0) | |
| Unknown |
60 (0.3) |
5 (0.8) |
0 (0.0) |
|
| Resident of a correctional facility at time of TB diagnosis | <0.001 | |||
| Y | 483 (2.5) | 27 (4.5) | 3 (5.8) | |
| N | 18,381 (97.1) | 559 (94.3) | 48 (92.3) | |
| Unknown |
68 (0.4) |
7 (1.2) |
1 (1.9) |
|
| Experiencing homelessness within past 12 mo | <0.001 | |||
| Y | 793 (4.2) | 78 (13.1) | 11 (21.1) | |
| N | 17,973 (94.9) | 504 (85.0) | 39 (75.0) | |
| Unknown |
166 (0.9) |
11 (1.9) |
2 (3.9) |
|
| Excess alcohol use within past 12 mo | <0.001 | |||
| Y | 1,683 (8.7) | 109 (18.4) | 10 (19.2) | |
| N | 16,961 (89.6) | 471 (79.4) | 38 (73.1) | |
| Unknown |
288 (1.5) |
13 (2.2) |
4 (7.7) |
|
| Noninjection drug use within past 12 mo | <0.001 | |||
| Y | 1,273 (6.7) | 124 (20.9) | 20 (38.5) | |
| N | 17,199 (90.9) | 446 (75.2) | 27 (51.9) | |
| Unknown |
460 (2.4) |
23 (3.9) |
5 (9.6) |
|
| Sputum smear | <0.001 | |||
| Positive | 8,909 (47.1) | 455 (76.7) | 45 (86.5) | |
| Negative | 7,863 (41.5) | 108 (18.2) | 5 (9.6) | |
| Not done | 2,142 (11.3) | 30 (5.1) | 2 (3.9) | |
| Unknown |
18 (0.1) |
0 (0.0) |
0 (0.0) |
|
| Cavitary disease§ | <0.001 | |||
| Y | 6,737 (35.6) | 402 (67.8) | 40 (76.9) | |
| N | 10,004 (52.8) | 173 (29.2) | 10 (19.2) | |
| Unknown |
2,191 (11.6) |
18 (3.0) |
2 (3.9) |
|
| Contact of infectious tuberculosis patient during prior 2 y | <0.001 | |||
| Y | 1030 (5.4) | 55 (9.3) | 7 (13.5) | |
| Unknown/not reported |
17,902 (94.6) |
538 (90.7) |
45 (86.5) |
|
| Median Social Vulnerability Index score (IQR)¶ | 0.73 (0.49–0.86) | 0.80 (0.64–0.89) | 0.86 (0.78–0.89) | <0.001# |
| Socioeconomic status | 0.65 (0.34–0.86) | 0.77 (0.56–0.88) | 0.84 (0.70–0.92) | <0.001# |
| Household characteristics | 0.46 (0.23–0.70) | 0.54 (0.31–0.74) | 0.57 (0.32–0.77) | <0.001# |
| Racial and ethnic minority status | 0.91 (0.78–0.97) | 0.91 (0.81–0.97) | 0.93 (0.83–0.97) | 0.01# |
| Housing type and transportation | 0.78 (0.61–0.90) | 0.82 (0.67–0.91) | 0.85 (0.68–0.91) | <0.001# |
*Values are no. (%) except as indicated. IQR, interquartile range; TB, tuberculosis. †χ2 test or Fisher exact test when <5 cases expected; indicates differences across the 3 categories. ‡Except for Hispanic or Latino, all are non-Hispanic. §Evidence of >1 lung cavities with chest radiograph, chest computerized tomography, or both. ¶Overall Social Vulnerability Index includes 16 US Census indicators from the 5-year American Community Survey grouped into 4 themes: socioeconomic status, household characteristics, racial and ethnic minority status, and housing type and transportation. Ranking values range from 0 to 1, and higher values indicate higher vulnerability and are merged to each case using the patient’s county of residence. #Kruskal-Wallis test.