What bacteria causes whooping cough?

Bordetella pertussis attaches to the lining of the airways and releases substances that irritate the breathing passages. This irritation can build into repeated bouts of coughing, sometimes followed by a sharp intake of breath or vomiting. Babies may have pauses in breathing rather than a recognisable whoop. A person can pass the infection to others when coughing, sneezing, or speaking, especially early in the illness. The bacterium is not the same as a virus, so treatment decisions may involve antibiotics rather than medicines aimed only at viral infections.

The cough may continue after the bacterium has been reduced because the airways need time to settle. A cough does not by itself prove that someone has pertussis; a clinician may use the symptom pattern, examination, and testing where appropriate. Read more about [Whooping Cough](/conditions/whooping-cough/) and the symptom [Cough](/symptoms/cough/).

Contact a healthcare professional if a cough is severe, comes in repeated spells, or follows close contact with someone diagnosed with pertussis. Mention the timing of exposure, whether the cough causes vomiting or breathing difficulty, and whether an infant or pregnant person may have been exposed. Keep distance from babies and other people at higher risk while arranging advice, cover coughs, wash hands, and improve ventilation. A clinician may prescribe [Antibiotic Treatment](/treatments/medical-management/antibiotic-treatment/) to reduce spread and, depending on timing and risk, to help manage the infection. Take prescribed medicine exactly as directed.

Vaccination lowers the risk of whooping cough and helps protect young children. Check whether routine [Childhood Immunisation](/treatments/preventive-care-and-vaccination/childhood-immunisation/) is up to date, particularly after a household exposure.

Seek urgent medical help for pauses in breathing, blue or grey lips, severe breathing difficulty, unusual drowsiness, dehydration, or a child who cannot feed because of coughing. Infants can become seriously unwell without producing the classic whoop. Arrange prompt clinical advice for a cough that is worsening, causes repeated vomiting, or is accompanied by fever or marked weakness. You can also read about [Fever](/symptoms/fever/) while deciding what information to share with the clinician.

Ask: Could this cough fit pertussis, and would testing change the plan? Should household contacts receive preventive advice or treatment? How long should the person stay away from babies, school, work, or gatherings? Which warning signs mean we should seek emergency care? When should routine vaccinations be checked or updated?