Cao D, et al. - Via a retrospective study, researchers examined the association between tuberculin skin test (TST) reaction size and active tuberculosis (TB) risk for college students. They determined the size of TST reaction and other factors associated with active TB risk by performing multivariable Cox regression. For this study, the inclusion of 67,292 college students was done in Beijing, China. They noted TST positive (≥10 mm) results in 8,021 (11.92%) individuals, and strong TST positive (≥15 mm) results in 3,879 (5.76%) of them. There were 26 active TB cases reported in 134,575 person-years with an incidence rate of 19.32 per 100000 person-years during the two-year follow up. College students were at an increased risk of active TB when the TST reaction size was ≥10 mm. The risk was higher among males vs females.