Table 2.
Characteristics and affected populations of large outbreaks of tuberculosis detected in the United States during 2014–2016a.
| Outbreak characteristics | Affected population | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Outbreak ID | Case count | No. states reporting outbreak cases | No. counties reporting outbreak cases | Median distance between patient pairs, km (miles)b | Median time from first to subsequent cases, yearsc | Percent U. S.-born | Percent in ethnic/racial minorityd | County incidence with/without outbreak cases (per 100,000)e | Ratiof | CDC SVIg |
| 1 | 17 | 3 | 5 | 200.4 (124.5) | 0.1 | 64.7 | 100.0 | 2.8/0.9 | 3.1 | 0.2 |
| 2 | 26 | 2 | 2 | 12.6 (7.8) | 3.9 | 80.8 | 100.0 | 5.4/4.8 | 1.1 | 0.8 |
| 3 | 19 | 1 | 1 | 0.0 (0.0) | 0.4 | 100.0 | 100.0 | 92.6/22.5 | 4.1 | 0.9 |
| 4 | 30 | 1 | 6 | 2.4 (1.5) | 0.7 | 93.3 | 96.7 | 8.0/1.4 | 5.7 | 0.2 |
| 5 | 19 | 1 | 6 | 37.0 (23.0) | 2.2 | 89.5 | 84.2 | 3.1/2.1 | 1.5 | 0.7 |
| 6 | 31 | 1 | 3 | 14.5 (9.0) | 1.9 | 90.3 | 45.2 | 6.8/6.0 | 1.1 | 0.9 |
| 7 | 20 | 2 | 3 | 0.0 (0.0) | 2.3 | 100.0 | 100.0 | 70.0/7.0 | 10.0 | 0.5 |
| 8 | 26 | 1 | 5 | 20.9 (13.0) | 2.4 | 100.0 | 96.2 | 6.7/3.2 | 2.1 | 0.9 |
| 9 h | 45 | 1 | NA | NA | 1.6 | 95.6 | 86.7 | NA | NA | NA |
| 10 | 18 | 1 | 2 | 3.1 (1.9) | 1.3 | 5.6 | 100.0 | 6.8/6.7 | 1.0 | 0.8 |
| 11 | 14 | 1 | 3 | 14.2 (8.8) | 2.0 | 71.4 | 100.0 | 4.7/4.5 | 1.0 | 0.8 |
| 12 | 25 | 2 | 3 | 1.9 (1.2) | 0.6 | 32.0 | 100.0 | 9.4/7.3 | 1.3 | 0.6 |
| 13 | 18 | 1 | 1 | 14.3 (8.9) | 1.1 | 100.0 | 100.0 | 6.1/5.7 | 1.1 | 0.7 |
| 14 | 38 | 1 | 15 | 198.0 (123.0) | 2.0 | 84.2 | 76.3 | 3.9/3.6 | 1.1 | 0.4 |
| 15 | 16 | 1 | 3 | 0.0 (0.0) | 0.4 | 100.0 | 62.5 | 5.1/1.8 | 2.8 | 0.3 |
| 16 | 42 | 1 | 8 | 0.0 (0.0) | 2.3 | 100.0 | 95.2 | 71.0/6.1 | 11.6 | 0.9 |
| 17 | 16 | 1 | 4 | 9.7 (6.0) | 1.4 | 100.0 | 37.5 | 4.8/4.5 | 1.1 | 0.8 |
| 18 | 11 | 1 | 1 | 5.5 (3.4) | 0.9 | 36.4 | 100.0 | 9.6/9.4 | 1.0 | 0.5 |
| 19 | 11 | 1 | 3 | 0.0 (0.0) | 1.6 | 100.0 | 100.0 | 63.4/0.0 | NA | 0.9 |
| 20 | 14 | 1 | 2 | 0.0 (0.0) | 0.4 | 100.0 | 100.0 | 77.6/17.5 | 4.4 | 0.9 |
| 21 | 10 | 1 | 3 | 17.2 (10.7) | 1.1 | 40.0 | 80.0 | 3.0/2.5 | 1.2 | 0.3 |
| 22 | 15 | 1 | 3 | 26.4 (16.4) | 2.0 | 100.0 | 100.0 | 1.2/0.6 | 2.0 | 0.4 |
| 23 | 17 | 3 | 4 | 11.1 (6.9) | 2.3 | 100.0 | 100.0 | 4.5/3.1 | 1.5 | 0.9 |
| 24 | 20 | 2 | 3 | 6.1 (3.8) | 2.2 | 100.0 | 85.0 | 3.3/2.1 | 1.6 | 0.5 |
| Total a | 18.5 (10–45) | 1 (1–3) | 3 (1–15) | 9.7 (6.0) (0–200.4 (124.5)) | 1.6 (0.1–3.9) | 97.8 (5.6–100) | 100.0 (37.5–100) | 6.1/4.5 (1.2–92.6/0–22.5) | 1.5 (1.0–11.6) | 0.7 (0.2–0.9) |
Large outbreaks detected during 2014–2016 could include cases reported from 2010 to 2018 because the surveillance time periods extend before and after the date of first detection. Values describing the totals represent the median (range).
Median distance between all case pairs based on the ZIP code centroid of reported residency at diagnosis; city of residence was used if ZIP code was missing.
Median time between the earliest reported case and each subsequent outbreak-related case during the 5-year outbreak surveillance period.
Ethnic/racial minorities include persons who were reported as a race or ethnic group other than non-Hispanic White.
Incidence rates were calculated for the county in which >50% of outbreak-related cases resided. For each outbreak, the county’s TB case counts with and without the outbreak-related cases were averaged over the respective 5-year outbreak surveillance periods and divided by the 2012–2016 American Community Survey county population estimates.
Ratio comparing the TB incidence rate with outbreak-related cases to the TB incidence rate without outbreak-related cases for the county in which >50% of outbreak-related cases resided.
The CDC Social Vulnerability Index (CDC SVI) uses 5-year U.S. Census data from the American Community Survey for 2012–2016 to describe the potential negative effects on communities caused by external stressors on human health. The CDC SVI ranks each county on 15 social factors within four overall themes, including socioeconomic status, household composition and disability, minority status and language, and housing type and transportation. Percentile ranking values range from 0 to 1, with higher values indicating greater vulnerability. Values ≤ 0.25 indicate low vulnerability; values > 0.25–0.5 indicate low-to-moderate vulnerability; values > 0.5–0.75 indicate moderate-to-high vulnerability, and values > 0.75 indicate high vulnerability. The CDC SVI is reported for the county of residence for >50% of cases in each large outbreak. See: Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry/Geospatial Research, Analysis, and Services Program. CDC Social Vulnerability Index 2016 Database US. https://www.atsdr.cdc.gov/placeandhealth/svi/data_documentation_download.html. Accessed on March 22, 2021.
County-level and distance measures could not be reported for this large outbreak due to surveillance artifacts with how residency data are reported by the state.