Comment on: Seroprevalence of Bordetella pertussis antibody in pregnant women in Iran.

The authors have indicated that 95% of objects have had complete immunization records against B. pertussis but only 35% had protective antibody against B. pertussis 1 . It has been proven that there is no accurate method to analyze the protection level after B. pertussis vaccination, so what does seropositive mean? It means that the object has recently caught the natural infection. Knowing this fact, it could be concluded that 35% of pregnant women have recently experienced pertussis infection. Impact of pertussis vaccine begins to wane 4 years after vaccination and is unmeasurable after 12 years, while average age of the subjects was 27.5 years old, about 15 years after the last dose of B. pertusis vaccine in Iran current vaccination schedule 2,3 .