Whooping Cough – Questions & Answers

Why do we vaccinate against pertussis (also called “whooping cough”)?

Pertussis is a bacterial respiratory illness characterized by severe spasms of coughing that can last for several weeks or even for months. Pertussis is usually spread from person-to-person through close contact with respiratory droplets released when a person coughs or sneezes. Before the introduction of vaccination in the 1940s, pertussis was a major cause of serious illness and death among infants and young children in the United States.

How many cases of pertussis are reported in the United States?

An average of more than 160,000 cases and more than 5,000 deaths were reported every year in the 1920s-30s. At its peak during this period, the annual number of case-reports was more than 250,000 with up to 9,000 deaths. In the 1940s, whole-cell pertussis vaccine combined with diphtheria and tetanus toxoids (DTP) was introduced, and case-reports of pertussis decreased more than 99% by 1976, when the number of reported cases reached a record-low of 1,010 cases.

Is pertussis reporting on the rise in the U.S.?

An increasing number of cases of pertussis have been reported to the CDC since the 1980s. The increases are greatest among adolescents (aged 10-19 years), but an increase is also seen among infants younger than 5 months old. The reported increases may reflect greater awareness of pertussis to some degree. Even with the increase in reports among adolescents and very young infants, the number of reported cases is more than 97 % lower than in the pre-vaccine era.

Why are we concerned about pertussis among infants?

Infants under the age of 12 months have more serious illness from pertussis and they are more likely to have complications and be hospitalized than persons in other age groups. In the 1990s, about two thirds of infants reported with pertussis were hospitalized. Infants are more likely to have pneumonia or convulsions. Infants also are at greatest risk of fatal pertussis. In recent years, 15 to 21 infant deaths from pertussis are reported to CDC annually.