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Background Reductions in tuberculosis (TB) transmission have been instrumental in lowering TB incidence in the United States. Sustaining and augmenting these reductions are key public health priorities. Methods We fit mechanistic transmission models to distributions of genotype clusters of TB cases reported to the Centers for Disease Control and Prevention during 2012–2016 in the United States and separately in California, Florida, New York, and Texas. We estimated the mean number of secondary cases generated per infectious case (R 0) and individual-level heterogeneity in R 0 at state and national levels and assessed how different definitions of clustering affected these estimates. Results In clusters of genotypically linked TB cases that occurred within a state over a 5-year period (reference scenario), the estimated R 0 was 0.29 (95% confidence interval [CI],.28–.31) in the United States. Transmission was highly heterogeneous; 0.24% of simulated cases with individual R 0  >10 generated 19% of all recent secondary transmissions. R 0 estimate was 0.16 (95% CI,.15–.17) when a cluster was defined as cases occurring within the same county over a 3-year period. Transmission varied across states: estimated R 0 s were 0.34 (95% CI,.3–.4) in California, 0.28 (95% CI,.24–.36) in Florida, 0.19 (95% CI,.15–.27) in New York, and 0.38 (95% CI,.33–.46) in Texas. Conclusions TB transmission in the United States is characterized by pronounced heterogeneity at the individual and state levels. Improving detection of transmission clusters through incorporation of whole-genome sequencing and identifying the drivers of this heterogeneity will be essential to reducing TB transmission. [ABSTRACT FROM AUTHOR]

Objectives. To understand the frequency, magnitude, geography, and characteristics of tuberculosis outbreaks in US state prisons. Methods. Using data from the National Tuberculosis Surveillance System, we identified all cases of tuberculosis during 2011 to 2019 that were reported as occurring among individuals incarcerated in a state prison at the time of diagnosis. We used whole-genome sequencing to define 3 or more cases within 2 single nucleotide polymorphisms within 3 years as clustered; we classified clusters with 6 or more cases during a 3-year period as tuberculosis outbreaks. Results. During 2011 to 2019, 566 tuberculosis cases occurred in 41 state prison systems (a median of 3 cases per state). A total of 19 tuberculosis genotype clusters comprising 134 cases were identified in 6 state prison systems; these clusters included a subset of 5 outbreaks in 2 states. Two Alabama outbreaks during 2011 to 2017 totaled 20 cases; 3 Texas outbreaks during 2014 to 2019 totaled 51 cases. Conclusions. Only Alabama and Texas reported outbreaks during the 9-year period; only Texas state prisons had ongoing transmission in 2019. Effective interventions are needed to stop tuberculosis outbreaks in Texas state prisons. (Am J Public Health. 2022;112(8):1170–1179. https://doi.org/10.2105/AJPH.2022.306864) [ABSTRACT FROM AUTHOR]