Lessons learned from two school tuberculosis investigations.

We describe the results from tuberculosis (TB) contact investigations of two high-school students. Following the development of active TB in two foreign-born students, contact investigations were performed to detect contacts with active TB disease or latent TB infection (LTBI). The two students developed pulmonary TB within 2 years of immigrating to the United States. Among household contacts, no case of active TB was identified; however, LTBI was identified in 7 of 20 persons screened (35%). Of the 104 high-risk school contacts identified, no cases of active TB disease were found, but 7 (9.3%) were diagnosed with LTBI. An additional 683 low-risk contacts were screened and 9 (1.5%) were positive. Schools and Public Health departments needs to be prepared for outbreak investigations and should screen only persons with a high risk of exposure to the index case with active TB in an attempt to identify secondary infections. Those persons with a low risk of exposure should not be screened.