Stephen J.LurieMD, PhD, Senior EditorIndividualAuthor
In Reply: We agree with Dr Reichler and colleagues
that documented TST conversion provides the purest estimation of recent transmission.
Unfortunately this event was uncommon in our study. Only 119 of 6113 contacts
converted between the first and second TSTs. We eliminated from the analysis
each contact who reported a positive TST result more than 60 days prior to
case identification. For those indicating no previous positive result and
an initial negative result, a second TST was performed 10 to 12 weeks later.
If the result of either the first or second test was positive, the contact
was classified as having a positive reaction. Prior TB exposure is confounded
by race, sex, and age; therefore, our model with demographics included is
designed to predict positive TST results. There are limitations to using this
outcome as a surrogate for recent transmission, including the background rate
of TB infection.
Bailey W, Gerald LB, Kimerling ME, Bruce F, Duncan S, Brooks CM, Dunlap NE, Redden DT, Tang S, Brook N. Factors in Tuberculosis Contact Investigations—Reply. JAMA. 2002;287(22):2944-2945. doi:10.1001/jama.287.22.2942