In countries with high rates of vaccination against pertussis, the incidence of this disease has decreased dramatically compared with the prevaccine era. However, pertussis still occurs in these countries, and severe morbidity and mortality are greatest among infants, particularly those who are unimmunized or incompletely immunized. Pertussis in older children and adults is perceived by many as being a mild disease, but it is a significant health burden in persons of all ages. Infants with pertussis experience the highest rates of hospitalization, complications and death. Severe complications include pneumonia, encephalopathy and meningoencephalitis. In addition, infants may experience weight loss, bronchitis, otitis media, apnea, cyanosis, inguinal hernia and rectal prolapse. It is essential to explore methods to prevent disease transmission to infants in the months before they complete their primary immunization series. The Global Pertussis Initiative was established to assess the true health burden of pertussis in infants and to suggest strategies to combat transmission and infection with Bordetella pertussis, which remains a significant public health concern.