Absence of antibodies against Bordetella pertussis in pregnant women and newborns in the state of Nuevo Leon.

Aims: To assess placental transfer of antibodies to the child at birth and at 2 months of age.

Materials And Methods: For the quantification of anti-PT IgG antibodies, we used an indirect enzyme-linked immunosorbent assay standardized by The National Institute of Epidemiologic Diagnosis and Reference (InDRE). Samples were considered negative from 0 to 48 IU/mL, indeterminate from 49 to 93 IU/mL and positive at ≥94 IU/mL.