Whooping cough is most serious in babies younger than
4 months of age. Usually, the younger the infant, the more serious the
illness.
In the United States in 2007:1
- Whooping cough occurred in about 4 people out of
100,000.
- People ages 10 to 20 had it more than any other age group.
- About 70 out of 100,000 infants younger than 6 months of age had it.
It is likely that a much higher number of people become infected with
whooping cough than is reported. This may be in part because teens and adults
usually have a milder form of the disease and don't see a doctor for treatment.
Also, doctors may not always recognize mild symptoms as being related to
whooping cough, and lab tests do not always detect the disease.