In Reply.—We appreciate McMillan and Weiner's concerns about misclassification of"exposed" and "unexposed" infants and the possible consequences for the results of our study.1 We would like to take the opportunity provided by their letter to comment further on these issues, since the effects of potential misclassification may not be widely appreciated.
McMillan and Weiner's first point concerns the possibility that infants born to women who received antibiotics that are effective against C trachomatis were misclassified as exposed to C trachomatis. As noted in our discussion of the results, we did not have information on the use of antibiotic therapies during the pregnancies of this group of women. However, misclassification of infants who were actually unexposed (because their mothers received antibiotics effective against C trachomatis) would exert a conservative bias on the results—that is, the associations we reported between exposure to C trachomatis and rates of pneumonitis and recurrent
SCHAEFER C, BOYCE WT, HARRISON HR. Infants Born to Women With Chlamydia trachomatis Infection-Reply. Am J Dis Child. 1985;139(12):1177-1178. doi:10.1001/archpedi.1985.02140140011003