Pertussis, or whooping cough, is a highly infectious disease of the respiratory tract caused by the gram-negative bacterium Bordetella pertussis. This disease spreads via droplet transmission (and to a lesser extent via fomites) and most commonly occurs in children. Typically, pertussis manifests in three stages, with the second and third stages characterized by intense paroxysmal coughing that is followed by a distinctive whooping sound on inhalation and, in some cases, vomiting. Young infants may not develop the typical cough, and often present with apnea and cyanosis instead. Patients who meet the should be started on and confirmatory laboratory studies (usually PCR or culture) should be conducted. is recommended for all close contacts and high-risk individuals (e.g., infants) regardless of immunization status. Pertussis immunization is part of the ; while immunization reduces the severity of illness it does not provide full immunity.
- Pertussis is typically a childhood disease (particularly children aged < 1 year); however, older patients are increasingly affected. 
- High rate of infections in newborns: The Tdap vaccine is recommended for pregnant individuals between 27 and 36 weeks' gestation. 
Epidemiological data refers to the US, unless otherwise specified.
- Pathogen: Bordetella pertussis is a gram‑negative, obligate aerobic coccobacillus.
- Transmission: droplet transmission, fomite transmission 
- Incubation period: on average 7–10 days (range 4–21 days)
- Proliferation of Bordetella pertussis on ciliated epithelial cells of the respiratory mucosa → production of virulence factors (e.g., tracheal cytotoxin) → paralysis of respiratory epithelium cilia and inflammation → secretion of inflammatory exudate into respiratory tract → compromise of small airways → cough, pneumonia, cyanosis 
- Bordetella pertussis produces pertussis toxin → ADP-ribosylation of the α subunit of Gi protein → inhibition of Gi protein → adenylate cyclase disinhibition → cAMP accumulation → impaired cell signaling pathways 
- Pertussis toxin is responsible for most of the systemic manifestations associated with whooping cough (e.g., hypoglycemia, lymphocytosis, modulation of host immune response).
- Neither vaccination nor actual infection confers complete or lifelong immunity.
Pertussis classically has three stages: catarrhal, paroxysmal, and convalescent. Symptoms may vary, however, based on age and immunization status; vaccinated individuals tending to have a milder illness without characteristic whooping. 
Catarrhal stage (1–2 weeks) 
- Nonspecific symptoms similar to an upper respiratory infection, e.g.:
- Patients are highly infectious.
Paroxysmal stage (2–6 weeks) 
Intense paroxysmal coughing (often occurring at night)
- Followed by a deep and loud inhalation or high-pitched whooping sound
- Accompanied by struggling for breath, gagging, and tongue protrusion
- Possibly accompanied by cyanosis
- Increases in frequency and severity throughout the stage
- Followed by the expulsion of phlegm or posttussive vomiting (risk of dehydration)
- Potential bleeding of the conjunctiva, petechiae, and venous congestion
- Infants (< 6 months) may present with: 
Convalescent stage (weeks to months) 
- Progressive reduction of symptoms
- Coughing attacks may persist over several weeks before resolving.
- Patients have an increased susceptibility to respiratory infections.
The typical pattern of paroxysmal cough with whooping manifests mainly in unvaccinated children. Infants < 6 months of age, vaccinated individuals, and adults may not whoop and may not follow the classic stages of pertussis. 
- Perform confirmatory studies for any patient that meets the suspected case definition for pertussis. 
- The choice of diagnostic test depends on duration since symptom onset. 
- For infants < 3 months, consider a CBC.
Suspected case definition for pertussis 
- Paroxysmal coughing
- Whooping on inspiration
- Posttussive vomiting
- Apnea 
- Known contact with confirmed case
- Living in an area with a pertussis outbreak
- Preferred test 
- Specimen collection
Bacterial culture 
- Gold standard 
- Indications 
- Specimen collection method
Pertussis serology 
- Used for patients who meet all the following criteria:
- Findings: ↑ IgG antibodies to pertussis toxin
- Start antibiotic therapy in without waiting for diagnostic confirmation. 
- Assess patients for admission criteria for pertussis and admit if present.
- Provide supportive care, e.g.: 
- Frequent suctioning
- Initiate measures to .
- After treatment, offer the to stable unvaccinated patients. 
Symptomatic treatment of cough (e.g., with corticosteroids, antihistamines, albuterol) is not recommended, as there is no evidence symptomatic treatments reduce cough or duration of hospitalization. 
Pertussis is a nationally notifiable disease. 
Admission criteria for pertussis
- Admit patients with features of severe disease, e.g.: 
- Consider admission for patients with risk factors for severe pertussis, e.g.: 
Antibiotic therapy for pertussis 
- First-line: macrolides
- Allergy/intolerance to macrolides: Consider trimethoprim/sulfamethoxazole: (off-label). 
Antibiotic therapy decreases transmission of pertussis but may not improve the duration or severity of symptoms, especially if started at a later clinical stage. 
- Infection: otitis media
- Cardiac: pulmonary hypertension 
- Neurologic: seizures, encephalopathy with possible permanent damage
- Sudden infant death 
We list the most important complications. The selection is not exhaustive.
- In children > 6 months: usually good; lengthy convalescence, but full recovery
- In children < 6 months: increased risk of complications; mortality highest in children < 2 months 
Primary prevention of pertussis 
- Vaccine: the acellular pertussis vaccine is available as a combination vaccine that also contains the diphtheria vaccine and tetanus vaccine.
- Choice of vaccine depends on age: 
- Primary course
- Contraindications 
Pertussis vaccination helps reduce severity, but infection can still occur because the immunity from vaccination (as well as infection) is short-lived and there has been a rise in vaccine antigen-deficient strains. 
Prevention of onward transmission of pertussis
- Use droplet precautions when evaluating patients.
- Advise isolation precautions for pertussis for suspected or confirmed cases.
- The duration of isolation precautions varies based on treatment status: 
- For patients in the community: 
- Advise avoiding contact with high-risk individuals (i.e., pregnant women, infants, and children).
- Children who attend daycare/school and staff in childcare and healthcare settings should remain at home.
- For hospitalized patients: Place the patient in a side room with droplet precautions. 
- Perform contact tracing to determine who should be offered .
- Pertussis is a notifiable disease; ensure the state health department has been contacted.
Postexposure prophylaxis for pertussis 
- All close contacts of an individual pertussis with, regardless of age and vaccination status 
- High-risk individuals with possible exposure, e.g.:
- Prophylactic measures