Pertussis

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Evidence-backed information EN 6/7 applicable sections · ZH 6/7 applicable sections Updated Oct 23, 2026

Pertussis, also called whooping cough, is a highly contagious bacterial respiratory disease caused mainly by Bordetella pertussis and prevented by vaccination ^[1]^[2]^[3]. Illness often starts with cold-like symptoms and can progress to prolonged paroxysmal cough, whooping, and post-tussive vomiting ^[1]^[2]^[4]. The disease remains endemic, has resurged worldwide, and has shifted in reported burden toward older children and adults while infants remain especially vulnerable ^[1]^[5]. Vaccination is the main public-health prevention strategy, but immunity can wane and pertussis persists in vaccinated populations ^[1]^[2].

Read the full clinical and epidemiological profile 7

Definition

Pertussis, also known as whooping cough or the 100-day cough, is a highly contagious, vaccine-preventable bacterial respiratory infection caused by Bordetella pertussis ^[2]^[1]. Following infection, initial symptoms generally appear 7 to 10 days later, reflecting a typical incubation period of about one week ^[2]^[1].

Clinical features

Initial presentation usually resembles a common cold, with mild fever, runny nose, and cough, which in typical cases gradually progresses to paroxysmal coughing fits followed by a characteristic high-pitched whoop on inhalation ^[2]^[1]. The severe coughing phase typically lasts 1–6 weeks but can persist for 10 or more weeks, and violent coughing may cause fatigue, vomiting, and rib fractures ^[1]. In children under one year of age, the classic cough may be minimal or absent, with episodes of apnea being the dominant manifestation ^[2]^[1]. Disease may still occur in vaccinated individuals, although symptoms are typically milder ^[1].

Epidemiology

Pertussis is endemic worldwide and remains one of the leading causes of vaccine-preventable deaths, with more than 264,000 cases reported globally in 2025 ^[2]. A 2017 study estimated an annual global burden of approximately 24 million cases and 160,000 deaths among young children, with about 90% of cases occurring in developing countries, though underreporting and underdiagnosis are widespread ^[1]. Pertussis has resurged worldwide over the past two decades, and epidemics occur cyclically every three to five years in both vaccinated and unvaccinated populations ^[5]^[1].

Transmission

Pertussis spreads easily from person to person, mainly through respiratory droplets generated by coughing or sneezing ^[2]^[1]. Affected individuals are infectious from the onset of symptoms until roughly three weeks into the paroxysmal coughing phase ^[1]. Although current vaccines substantially reduce severe disease, they are less effective at preventing infection and onward transmission of B. pertussis, contributing to continued spread even in highly vaccinated populations ^[6].

Risk groups

Individuals whose immunity from vaccination has waned remain at risk, because pertussis has persisted in vaccinated populations and resurgence has been attributed to waning immunity ^[1]. Populations in Western countries with widespread vaccination also remain affected, where pertussis is one of the most common vaccine-preventable diseases ^[1].

Prevention

Pertussis prevention is mainly by vaccination, which is effective and recommended for routine use by WHO and CDC; the multi-component acellular vaccine is estimated to be 71–85% effective, with greater effectiveness against more severe strains ^[1]. Protection decreases over time, so additional doses are often recommended for older children and adults ^[1]. Immunizing pregnant women is a favorable strategy expected to prevent pertussis cases, hospitalizations, and deaths in infants younger than one year ^[3]. Despite widespread vaccination, pertussis has persisted in vaccinated populations and remains one of the most common vaccine-preventable diseases in Western countries ^[1].

References

1 Wikipedia contributors. Whooping cough - Wikipedia [Internet]. Wikipedia. cited 3 Sept 2026. Available from: https://en.wikipedia.org/wiki/Whooping_cough
2 World Health Organization. Pertussis [Internet]. cited 3 Sept 2026. Available from: https://www.who.int/health-topics/pertussis
3 Nieves DJ et al. Bordetella pertussis. Microbiol Spectr. 2016 Jun. PMID: 27337481. doi: 10.1128/microbiolspec.EI10-0008-2015. PubMed: https://pubmed.ncbi.nlm.nih.gov/27337481/
4 Kinkade S et al. Acute Bronchitis. Am Fam Physician. 2016 Oct 1. PMID: 27929206. PubMed: https://pubmed.ncbi.nlm.nih.gov/27929206/
5 Mi YM et al. Expert consensus for pertussis in children: new concepts in diagnosis and treatment. World J Pediatr. 2024 Dec. PMID: 39537933. doi: 10.1007/s12519-024-00848-5. PubMed: https://pubmed.ncbi.nlm.nih.gov/39537933/
6 Locht C et al. Pertussis before, during and after Covid-19. EMBO Mol Med. 2025 Apr. PMID: 39994481. doi: 10.1038/s44321-025-00199-2. PubMed: https://pubmed.ncbi.nlm.nih.gov/39994481/