Pertussis is highly communicable. In households, attack rates are 80-100% among unimmunized contacts and 20% among immunized contacts.

• Pertussis remains an important cause of infant morbidity and death in developing countries, with ~195,000 childhood deaths worldwide in 2008.
• In the United States, although the incidence of pertussis has decreased by >95% because of universal childhood vaccination, >40,000 cases were reported in 2012, with increasing rates among adolescents and adults.
• Persistent cough of >2 weeks' duration in an adult may be due to B. pertussis in 12-30% of cases.
• Severe morbidity and mortality are restricted to infants <6 months of age.