To characterize the natural antibody response to B. pertussis we determined levels of IgG, not only against the well-studied vaccine antigens Ptx, FHA, Prn, Fim2 and Fim313,16, but also against Vag8, BrkA, LOS and OMVs using paired plasma samples of symptomatic and recovered pertussis patients and controls (Fig. 1). This evidence concerns the gene CIAO3 and pertussis.