The Conversation | "Whooping cough is making a comeback, but the vaccine provides powerful protection"

Dr. Annette Regan, assistant professor in the UCLA Fielding School's Department of Epidemiology, was interviewed for a Q&A by The Conversation about why pertussis, also known as whooping cough, has become so prevalent and how families can protect themselves from the disease.

Pertussis, a bacterial infection that can be especially dangerous for babies and young children, is on the rise. Already in 2025 the U.S. has recorded 8,485 cases. That’s compared with 4,266 cases during the same period in 2024.

Q: What is pertussis and why is it dangerous?

Pertussis is a vaccine-preventable disease caused by the bacterium Bordetella pertussis. Researchers in France first identified the B. pertussis bacterium in 1906. The first recorded epidemic of pertussis is thought to have occurred in Paris in 1578.

Infection can cause an acute respiratory illness characterized by severe and spasmodic coughing spells. The classic symptom of pertussis is a “whoop” sound caused by someone trying to breath during a bad cough. Severe complications of pertussis include slowed or stopped breathing, pneumonia and seizures. The disease is most severe in young babies, although severe cases and deaths can also occur in older children and adults. 

Some doctors call pertussis “the 100-day cough” because symptoms can linger for weeks or even months.

The World Health Organization estimates that 24.1 million pertussis cases and 160,700 deaths occur worldwide in children under 5 each year. Pertussis is highly contagious. Upon exposure, 80% of people who have not been previously exposed to the bacterium or vaccinated against the disease will develop an infection. 

Fortunately, the disease is largely preventable with a safe and effective vaccine, which was first licensed in the U.S. in 1914.

Read the full Q&A in The Conversation.