9.20. Whooping Cough (Pertussis)

Updated 4 June 2026

Guidelines for Managing Whooping Cough (Pertussis)

This guidance is intended to assist healthcare workers in the management of patients, staff, and visitors who present with symptoms suggestive of whooping cough. These guidelines should be implemented to prevent and control the spread of infectious diseases and to help avert outbreaks.

Overview

Whooping cough, also known as pertussis, is a highly contagious bacterial respiratory infection caused by Bordetella pertussis. It is characterized by severe coughing spells that can end with a “whooping” sound when the person breathes in. It is particularly dangerous for infants, young children, and vulnerable populations.

Mode of Transmission

Route	Description
Primary route	Airborne transmission through respiratory droplets when an infected person coughs, sneezes, or talks.
Close contact	Direct contact with discharges from respiratory mucous membranes of an infected person, or contact with surfaces contaminated with respiratory secretions.

The disease is frequently brought home by an older sibling or a parent.

Incubation Period

The incubation period typically ranges from 7 to 10 days but can extend up to 21 days.

Period of Communicability (Infectious Period)

Whooping cough is highly communicable from the onset of catarrhal symptoms before the paroxysmal cough stage.
Communicability gradually decreases and is negligible after 3 weeks for ordinary non-familial contacts, despite persisting spasmodic cough with whoop.

Susceptibility and Resistance

There is no clear evidence of effective trans-placental immunity in infants.
It is predominantly a childhood disease, with incidence rates highest in the under-5 age group.
One attack usually confers prolonged immunity, although second attacks can occur occasionally.
Cases in adolescents and adults occur because of incomplete immunizations and waning immunity.

Clinical Signs and Symptoms

Whooping cough progresses through three stages:

Stage	Typical Duration	Key Features
Catarrhal stage	1–2 weeks	Mild, cold-like symptoms, including runny nose, sneezing, low-grade fever, and mild cough. The patient is highly contagious during this stage.
Paroxysmal stage	1–6 weeks	Severe coughing fits, known as paroxysms, followed by a “whooping” sound during inhalation. Vomiting or exhaustion may occur after coughing spells.
Convalescent stage	Weeks to months	Gradual reduction in coughing frequency and severity. Cough may persist for weeks or months.

Complications

Infants and Young Children

Pneumonia
Seizures
Encephalopathy
Apnea
Death

Adolescents and Adults

Weight loss
Rib fractures
Urinary incontinence
Syncope due to severe coughing

Diagnosis

Clinical Evaluation

Diagnosis is based on symptoms, especially the characteristic “whoop” and prolonged cough.

Laboratory Tests

Please complete the Ezra Long Communicable Disease Laboratory Requisition Form requesting testing for Bordetella pertussis when taking a nasopharyngeal swab on a suspected case.

Serology may be used to detect antibodies, particularly in later stages of illness, from 4–12 weeks after cough onset.

Specimen Collection

Time from Cough Onset	Recommended Specimen	Key Instructions
Within 4 weeks	Nasopharyngeal swabs for culture and PCR	Ideally collect two nasopharyngeal swabs: one for culture and one for PCR. Specimens can be collected up to four weeks after cough onset; after this period, detection by culture or PCR is reduced. Do not collect throat swabs or anterior nasal swabs. Use sterile polyester, rayon, or nylon flocked swabs. Do not use cotton swabs. A saline nasopharyngeal aspirate may be collected as an alternative.
4–12 weeks	Serum sample for IgG anti-pertussis toxin antibody testing	Do not use serology in children 10 years of age or younger due to lack of sensitivity. Do not use serology in patients vaccinated within one year due to persistence of IgG antibodies.

Figure 1: Timeline of clinical disease and laboratory diagnostics relative to point of infection.

Case Definitions

Suspected Case

A person of any age with a cough lasting 2 weeks or longer, or of any duration in an infant or any person in an outbreak setting, without a more likely diagnosis and with at least one of the following:

Paroxysms or fits of coughing
Inspiratory whooping
Post-tussive vomiting, or vomiting without other apparent cause
Apnea, only in infants younger than 1 year of age
Clinician suspicion of pertussis

Note: Pertussis in immunized or previously infected individuals can present without classic signs and may not be captured by the above case definition.

Confirmed Case

A confirmed case may be determined by laboratory confirmation or epidemiological linkage.

Laboratory-confirmed Case

A person who meets the suspected case definition with laboratory confirmation by either of the following:

Detection of genomic sequences of B. pertussis by PCR assay meeting performance criteria; or
Elevated IgG antibodies to pertussis toxin in an individual 11 years of age or older, one year or longer after the last vaccine dose.

Epidemiologically Linked Case

A person meeting the suspected case definition with close contact to a laboratory-confirmed case, or another epidemiologically linked case in an outbreak setting, in the three weeks prior to onset of cough.

Possible Case

A person who meets the suspected case definition but does not meet confirmed classification. This includes suspected cases who did not have laboratory testing done and those who tested negative.

Prevention and Control

Vaccination

Current vaccination coverage in Saint Lucia is 89% as of 2024.
Ideal coverage is 95% and above.
Continued advocacy for vaccination is essential.
Pregnant women should receive DT during each pregnancy, preferably between 27–36 weeks gestation, to protect newborns through passive antibody transfer.
DPT is given from 2 months to 5 years.

Isolation and Quarantine

Exposed household members and close contacts should receive prophylactic antibiotics.

Antibiotic Prophylaxis

Update 2024: Azithromycin is now the preferred first-line agent for both treatment and post-exposure prophylaxis due to its shorter course, superior tolerability, and equivalent efficacy to erythromycin. Erythromycin remains an acceptable alternative.

Management of Contacts

Definition of a Close Contact

A close contact is a person with face-to-face exposure, within 1 metre, to an infectious case for a single period of at least one hour. This also includes family and household members and, in other settings, people who have stayed overnight in the same room as the case.

Asymptomatic Close Contacts

Asymptomatic close contacts are not contagious and do not need to be excluded from social settings. They should be monitored for the development of symptoms for 21 days following last exposure.

Symptomatic Contacts

If symptomatic contacts have already coughed for 21 days at the time of diagnosis, the individual is no longer contagious and isolation is not indicated.
Symptomatic contacts who refuse antibiotics should stay home, excluding school, child care, work, church, and other social settings, for 21 days after cough onset. During this period, they should not receive visitors.

Key Messages for Healthcare Workers

Maintain a high index of suspicion for whooping cough, especially in infants and unvaccinated individuals, particularly those residing in communities where an infected case has stayed.
Ensure nasopharyngeal swab specimen collection from any suspected case of whooping cough.
Immediately notify any suspected cases to the Epidemiology Unit at the Ministry of Health.
Advocate for vaccination as the most effective preventive measure for unvaccinated persons.
Use azithromycin as first-line antibiotic for treatment and prophylaxis unless contraindicated.

Reporting requirement: All suspected cases of Whooping Cough (Pertussis) MUST be reported to the Epidemiology Unit at the Ministry of Health within 24 hours.

Reference List

World Health Organization. (2023). Surveillance Vaccine Preventable Diseases: Pertussis. Available from: https://cdn.who.int/media/docs/default-source/immunization/vpd_surveillance/vpd-surveillance-standards-publication/who-surveillancevaccinepreventable-16-pertussis-r2.pdf
Centers for Disease Control and Prevention. (2024). Pertussis (Whooping Cough): Clinical Features. Available from: https://www.cdc.gov/pertussis/clinical/index.html
Pan American Health Organization / World Health Organization. (2024). Pertussis: Epidemiological Alerts and Updates.