More importantly, have the authors made a convincing case that CT scanning should be routinely incorporated into TB contact investigations? I do not think so. First, as noted above, this outbreak seems extraordinary and hardly typical of the usual experience. Even without CT scanning, at least 10% of contacts would have been diagnosed with active TB, a much higher prevalence than generally seen, as noted above. Most contact investigations do not yield this number of secondary cases, and the yield of CT scanning could not be expected to be as high. Second, most of the patients who were said to have TB diagnosed on the basis of CT scanning alone had symptoms that although nonspecific were certainly suggestive of active TB. They might have been diagnosed on clinical suspicion and sputum cultures alone. Third, CT scanning in most countries is significantly more expensive than plain chest radiography and beyond the resources of most public health departments. Fourth, CT scanning of the chest administers a significantly higher radiation dose than plain radiography and unnecessarily exposes a healthy, young population to unknown, but probably real, future risks.