However, perturbations in the vaginal flora that increase the prevalence of indole-producing bacteria during bacterial vaginosis (BV) may increase the susceptibility of women to extended infections even in the face of a robust IFNγ response, a hypothesis originally proposed by Caldwell and co-workers in a seminal Journal of Clinical Investigation study in 2003 (Caldwell et al., 2003). This evidence concerns the gene IFNG and bacterial vaginosis.