Whooping cough is a respiratory tract infection caused by Bordetella pertussis, a gram-negative bacterium. It can affect people of all ages. It causes coughing fits so severe that the child cannot inhale between coughs, resulting in a distinctive “whooping” sound as they forcefully draw in the air afterwards.
Bordetella pertussis is infectious for three weeks after the onset of cough (or until 48 hours after starting antibiotics).
Children and pregnant women are vaccinated against pertussis. When the vaccine is given in pregnancy, the mother’s antibodies cross the placenta and help protect the newborn. The vaccine’s protection decreases over time.
Presentation
The approximate timeline for whooping cough (with significant variation):
- The incubation period lasts around 1 week
- Coryzal symptoms lasting around 1 week (e.g., blocked and runny nose, sore throat and mild dry cough)
- Severe paroxysmal cough lasting 1-10 weeks
- Recovery can take weeks to months
These severe coughing attacks occur suddenly and repeatedly, with periods of no coughing in between, known as a paroxysmal cough. The cough may be more frequent at night. The fits can be so intense that the patient runs out of breath, and when the coughing stops, a loud, high-pitched whoop is usually heard as they breathe in. Not all patients will produce the whooping sound. Infants with pertussis may develop apnoea (pauses in breathing).
In some cases, the coughing is so forceful that it may cause:
- Fainting
- Vomiting
- Subconjunctival haemorrhage
- Facial petechiae
- Pneumothorax
- Rib fractures
- Hernias
- Intervertebral disc herniation
Diagnosis
A nasopharyngeal or nasal swab, with PCR testing or bacterial culture, can confirm the diagnosis if taken within 3 weeks of cough onset.
When the cough has been present for more than 2 weeks, and patients have not been vaccinated in the past year, they can be tested for anti-pertussis toxin immunoglobulin G antibodies using an oral fluid or blood sample. These are antibodies produced by the immune system in response to pertussis toxin.
Management
Pertussis is a notifiable disease, and the UK Health Security Agency (UKHSA) must be notified of all suspected and confirmed cases. Vulnerable or acutely unwell patients (e.g., under 6 months or apnoeas) may need admission. Preventing the spread is important. Patients should avoid contact with vulnerable people, dispose of tissues, and maintain hand hygiene.
NICE CKS (2024) recommends that patients need to stay off nursery, school or work until either:
- 48 hours of appropriate antibiotics
- 14 days from the onset of the cough (or 21 days for higher-risk work, such as caring for infants or pregnant women)
Antibiotics are started when the cough onset is within 14 days (or 21 days if they have contact with vulnerable infants). Antibiotics reduce transmission but may not significantly improve symptoms. Options are:
- Macrolides first-line (e.g., azithromycin, erythromycin and clarithromycin)
- Co-trimoxazole (if macrolides are unsuitable)
Prophylactic antibiotics (macrolides first-line) are recommended for close contacts in priority groups, for example:
- Unvaccinated infants
- Pregnant women over 32 weeks gestation
- People who have close contact with infants or pregnant women
Prognosis
Symptoms often improve gradually over weeks, but the cough can persist for months. It is known as the “100-day cough” because of its potentially long duration.
Key short-term complications are feeding difficulty and weight loss, pneumonia, apnoea and seizures. Rarely it can cause death in young infants.
Last updated May 2026
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