More than half of the new tuberculosis cases occur in foreign born immigrants in the United States. According to a study in the Journal of the American Medical Association, 53% of the total TB cases in the U.S. among foreign-born persons occurred in the 22% of the population born in sub-Saharan Africa and Southeast Asia regions. The study also reported a decline in TB case rates among the foreign-born population overall, but even more than 20 years after arrival it remained higher than among U.S. born persons.

Drug resistant TB was found to be the highest in Vietnam, Peru, the Philippines and China among others. Experts feel screening immigrants and refugees from the Philippines and Vietnam would have detected almost half the average 250 TB cases that came into the U.S. every year between 2001 and 2006, and immigrants from Africa and Southeast Asia should be tested and treated for TB before their arrival to prevent the spread of the disease.  

A study of case rates showed that individuals born in most countries of sub Saharan Africa had annual case rates of more than 250 per 100,000 persons for the first two years of entry into the U.S.  Those born in Central America, Eastern Europe, the Pacific Islands, and South, East, and Central Asia had annual rates of 100 per 100,000 persons while the lowest risk was among those born in Western Europe, Canada, Australia, and New Zealand, all of which had rates of less than 10 per 100,000 persons.

Kevin P. Cain of the Centers for Disease Control and Prevention felt that with an excess of 37 million foreign born people living in the US, finding and testing all of them for latent TB infection was not possible. So their study was designed to target latent screening efforts by examining the risk of TB and drug-resistant disease among subgroups of foreign-born individuals.

The CDC researchers concluded that though neither testing nor treatment for latent TB can be implemented as recommended, its yield could be better by focusing on the highest-risk groups of foreign-born persons first. This could be easily handled through overseas diagnosis and treatment of latent TB before immigration, the current nine-month regimen for treating latent TB makes this strategy impractical.