I was interested to read the paper by Chin et al. [1] that looked at the association of Chlamydia trachomatis ompA genovars and trachoma phenotypes. In their study in Ethiopia, they found that the 93 B genotypes were somewhat more likely to be associated with more severe disease than the 258A genotypes that they identified. Although their report is brief, they may be interested in studies done in a non-human primate mode that did show that there is not only some variation between different serovars in the clinical response they induce, but also some variation within different strains of serovar [2]. At the time this previous work was done, it was not possible to genotype isolates and so the genetic variation is unknown, although the clinical variation is also quite marked.