Pertussis is easily spread when an infected person coughs or sneezes. Pertussis can cause spells of violent coughing and choking in young children, making it hard to drink, eat, or even breathe. Children often make a "whooping" noise when they breathe in after a hard coughing attack, which is why this disease is often called whooping cough. The cough can last for weeks.

What does Pertussis sound like?

• Listen to a audio sample of a child with Pertussis

This disease is most serious for babies under a year old. Pertussis may cause serious health problems: about 1 child in 10 with pertussis also gets pneumonia; about 20 in every 1,000 will have convulsions; and in 4 of every 1,000 the brain will be affected. There are pertussis outbreaks every year because children are not immunized. Pertussis kills about 300,000 children per year in countries where children don't get immunized.

Pertussis is thought of as a childhood disease, but we now know that adults can get pertussis as well. Adults who get pertussis have a cough, but don't "whoop". Unfortunately, many adults with pertussis are not treated by their doctor and pass this disease on to others, possibly young children.

Pertussis vaccine is given to young children in the DTaP (diphtheria, tetanus, and acellular Pertussis) vaccine series and to adolescents and adults in the DTaP (diphtheria, tetanus, and acellular Pertussis) vaccine.