Pertussis Immunization Programs in Low Income Countries

Due to waning of infectious as well as vaccine immunity and lack of vaccination boosters, a large number of adolescents and adults are no longer immunized against Bordetella pertussis, the agent of whooping cough and consequently may contract whooping cough. Furthermore, these populations represent a reservoir of the infectious agent from which the dissemination to non-immune infants is possible, causing severe illness, or even death, in this age group. Few studies have been carried out on whooping cough in developing countries (incidence, contaminator's age, etc.) and, specifically, none have assessed the duration of protection induced by the whole cell pertussis (wP) vaccine mainly presently used in these countries. However, data on the duration of vaccine induced protection are essential to determine i) the usefulness of vaccine boosters and ii) the target age group for these boosters. The aims of the present study are: * To evaluate the proportion of confirmed pertussis cases in infants presenting whooping cough syndrome (WP1a) * To evaluate the proportion of confirmed pertussis cases or healthy carriers among contact cases * To determine origin of the infant's contamination (WP1b) * To determine the duration of protection induced by the wP vaccines used in contact cases and the child population aged 3 to 15 yo (WP1b and WP2) * To bring new scientific evidences documenting the potential need for initiating boosters (WP1b and WP2) * To allow a comparison of the results with those obtained using the same methodology for the acellular pertussis vaccine and/or in other contexts. Potential implications for the use of pertussis vaccines in low and moderate income countries. * To increase local capabilities by the transfer of materials and expertise that will make the diagnosis of pertussis possible in the centres of reference and strengthen a pertussis monitoring network in the implicated countries. * To improve children's health through a better match of the vacc