Clinical Guides
Whooping Cough (Pertussis)
An India-contextualised, clinically focused guide to recognising pertussis, testing and notifying safely, limiting transmission, treating early, protecting contacts and identifying infant and pregnancy emergencies.
MedNext Academy | 12 min read
Whooping Cough (Pertussis)
An India-contextualised, clinically focused guide to recognising pertussis, testing and notifying safely, limiting transmission, treating early, protecting contacts and identifying infant and pregnancy emergencies.
Summary
Whooping cough, or pertussis, is a respiratory infection caused mainly by Bordetella pertussis. It often begins like a nonspecific upper-respiratory illness and then develops into repeated coughing bouts, inspiratory whoop or post-tussive vomiting; infants may instead have apnoea, cyanosis, poor feeding or exhaustion without a whoop. Vaccination reduces risk and severity but does not make pertussis impossible, because immunity and protection can wane. [CDC 2025a]
A clinically compatible illness, known exposure or high-risk contact should trigger early testing and public-health communication according to the local pathway. Nasopharyngeal PCR or culture is time- and specimen-dependent; a negative late test does not automatically exclude disease. Treat suspected cases promptly when the clinical or epidemiological risk is meaningful, especially when an infant, pregnant person near delivery or vulnerable household member could be exposed. Antibiotics reduce transmission and may help most when started early, but they should not be advertised as a reliable way to shorten an established paroxysmal cough. [CDC 2025b]
Keep a suspected infectious patient away from close contact until five days of effective antibiotic therapy have been completed, or for the applicable public-health period when treatment is not given. Assess breathing, hydration, feeding and complications at every review. This guide is educational and does not replace emergency assessment, local notification rules, a microbiology result or a paediatric treatment protocol.
How Common Is It?
Pertussis occurs in cycles and can return when population immunity, diagnostic recognition or vaccine coverage changes. Infants are at greatest risk of hospitalisation, apnoea, pneumonia, seizures, encephalopathy and death, particularly before completion of the primary infant series. Adolescents and adults may have a prolonged cough without a classic whoop and can transmit infection to a newborn. [WHO 2015]
Clinical recognition is often delayed because early catarrhal symptoms resemble a common cold and vaccinated people may have milder disease. A cough lasting weeks does not prove pertussis, but repeated paroxysms, vomiting, an inspiratory whoop, exposure or an outbreak setting should change the threshold for testing and treatment. Do not use the absence of fever or a whoop to dismiss the diagnosis.
In India, pertussis surveillance sits within the vaccine-preventable disease surveillance system and outbreak signals may be handled through district and state public-health teams. NCDC describes pertussis among priority diseases in its surveillance system. [NCDC 2026] Availability of PCR, culture, isolation rooms and contact tracing varies. A practical plan names the nearest paediatric-capable facility, laboratory and district surveillance contact rather than promising a test or medicine that is not locally available. Record age, vaccination history, onset, exposure, pregnancy or infant contact and current severity.
Risk Factors
The major risk factor for severe disease is young age, particularly an infant under one year and especially the first months of life. Incomplete or delayed primary immunisation, prematurity, chronic lung or neurological disease, immune compromise and inability to feed increase concern. Household crowding, childcare, maternity or neonatal settings and direct exposure to a coughing case increase transmission risk. Vaccination status should be checked, but a current record does not rule out pertussis or remove the need for evaluation. [CDC 2025c]
Pregnancy requires two separate questions: could the pregnant person have pertussis, and could they expose a newborn soon? Third-trimester contact with an infectious case is a public-health concern because the newborn may be too young to be protected. Coordinate obstetric, paediatric and infectious-disease advice; do not postpone assessment until delivery. WHO supports pertussis vaccination strategies in pregnancy where adopted by national programmes, with local schedule and product guidance taking priority. [WHO 2015]
Risk also reflects service access: delayed presentation, long travel, limited oxygen or paediatric observation, and inability to isolate affect the safe pathway. Ask about macrolide allergy, QT-risk medicines, liver disease and previous antibiotics before prescribing. Do not use risk labels to stigmatise a family or infer vaccine refusal; document the actual history, barriers and support needed.
Diagnosis
History
Record cough onset and progression, coryza, paroxysms, whoop, vomiting, apnoea, cyanosis, syncope, chest pain, fever, feeding, urine output and sleep. Ask about age, pregnancy, prematurity, immunisation dates, household and childcare exposure, known outbreak, travel, prior antibiotics and comorbidity. Determine whether the patient has contact with an infant, pregnant person near term, frail adult or immunocompromised person. A vaccinated adolescent or adult may have atypical illness.
Examination
Assess airway, work of breathing, respiratory rate, oxygen saturation, colour, mental state, hydration and ability to feed or speak. Observe a cough only when safe; do not provoke prolonged paroxysms. Look for apnoea, bradycardia, cyanosis, exhaustion, dehydration, pneumonia, otitis, weight loss, hernia or subconjunctival haemorrhage. In infants, absence of a whoop is not reassuring. Recheck after a coughing bout because an apparently comfortable interval can hide deterioration.
Investigations
Take a properly collected nasopharyngeal specimen for PCR and/or culture according to illness duration and local laboratory guidance. Culture is most useful early and before antibiotics; PCR is generally more sensitive but late testing can be falsely negative. Serology has a limited, timing-dependent role and is not a substitute for a local protocol. A chest radiograph, blood gas or other test is guided by severity or suspected complication, not used routinely to “confirm” uncomplicated pertussis. Do not delay emergency support or appropriate treatment while waiting for a result.
Differential Diagnosis
The early phase overlaps with viral upper-respiratory infection, influenza, COVID-19, respiratory syncytial virus and bacterial pneumonia. Paroxysmal cough can also occur with asthma, airway foreign body, croup, tuberculosis, mycoplasma infection, chlamydial infection, gastro-oesophageal reflux or post-viral cough. Apnoea or cyanosis in an infant is an emergency syndrome, not a diagnosis to observe at home. Consider sepsis, bronchiolitis, cardiac disease, metabolic illness and neurological causes when the presentation is atypical.
A barking cough suggests croup but does not exclude co-infection. Sudden onset with choking raises foreign body concern. Prolonged fever, focal chest signs, hypoxaemia or toxic appearance should prompt assessment for pneumonia or another serious infection. In India, tuberculosis and measles-related respiratory illness may enter the differential according to exposure, vaccination and clinical context; follow the relevant testing and notification pathway rather than labelling every prolonged cough as pertussis.
The differential does not justify broad empiric antibiotics without a working diagnosis. Test selection and isolation depend on the most hazardous plausible condition. If PCR is negative but the clinical picture and exposure are compelling, review specimen timing, prior antibiotics and an alternative diagnosis with microbiology or infectious-disease support. A positive molecular result should not be interpreted as proof that every cough symptom is caused by pertussis or that complications are absent.
Management
Stabilise first. Infants, people with apnoea or cyanosis, hypoxaemia, dehydration, repeated vomiting, exhaustion, altered consciousness, seizures or respiratory distress need urgent hospital assessment. Use age-appropriate oxygen, suction, hydration and feeding support; avoid upsetting an infant unnecessarily because handling can trigger paroxysms. Monitor for pneumonia, apnoea and inability to maintain intake. Do not give sedating cough remedies to a child without specialist advice.
For a stable suspected case, collect the recommended specimen promptly and start a current guideline-concordant antibiotic when the clinical/public-health benefit outweighs delay, particularly with early illness, severe-risk contacts or a likely exposure. Macrolides are commonly recommended; choice, dose, duration, age restrictions, interactions and local resistance guidance must come from the current protocol. Antibiotics are primarily about reducing viable organisms and transmission; established cough may continue because airway injury and hypersensitivity persist. [CDC 2025b]
Use respiratory hygiene, ventilation, masking where feasible and separate sleeping or care arrangements. Exclude symptomatic cases from school, childcare or healthcare contact until five days of effective therapy, or follow local public-health instructions. Notify and cooperate with contact tracing through the appropriate district or state service. A household plan should include symptom monitoring for 21 days after exposure, clear emergency triggers and practical support for medicines, transport and isolation.
Prescribing Information
Pertussis treatment and post-exposure prophylaxis use similar antibiotic classes but are different clinical decisions. CDC identifies azithromycin, clarithromycin and erythromycin as recommended macrolides, with trimethoprim-sulfamethoxazole an alternative for people aged two months or older when appropriate. [CDC 2025b] The prescriber must verify weight, age, pregnancy, allergy, hepatic function, QT prolongation, interacting drugs and the local Indian protocol. Do not copy a dose from an adult into an infant or use leftover antibiotics.
Start treatment as early as practical when suspicion is meaningful; CDC gives a reasonable timing framework of within three weeks of cough onset for people aged one year or older, within six weeks for infants under one year and within six weeks for pregnant women, especially near term. [CDC 2025b] These windows do not replace specialist judgement. Antibiotics are not a promise of rapid symptom resolution and should not be used indiscriminately for every prolonged cough.
Offer PEP selectively to household contacts and people at high risk or likely to contact someone at high risk, in coordination with public health. CDC supports PEP for asymptomatic household contacts within 21 days of index-cough onset and high-risk people within 21 days of exposure. [CDC 2025d] Vaccination catch-up remains important but does not substitute for indicated PEP. Document counselling, adherence, adverse effects, isolation end date, notification and review.
When to Refer
Refer urgently to paediatrics or emergency care for an infant with cough, apnoea, cyanosis, poor feeding, repeated vomiting, lethargy, dehydration, hypoxaemia, bradycardia, seizures or respiratory distress. A pregnant person with suspected pertussis, particularly near delivery, needs coordinated obstetric and infectious-disease review because treatment, isolation and newborn protection are time-sensitive. Refer any patient with pneumonia, haemoptysis, syncope, encephalopathy, severe weight loss, inability to take medicine or deterioration despite treatment.
Discuss with microbiology or infectious diseases when illness is atypical, PCR and clinical findings conflict, a resistant organism is possible, the patient is immunocompromised, or a cluster requires coordinated testing and control. Public-health referral is part of treatment: report suspected or confirmed disease according to Indian state and district rules, support contact identification and follow the current outbreak definition. NCDC’s VPD surveillance includes pertussis, but local reporting routes must be verified. [NCDC 2026]
In settings without PCR, paediatric observation or isolation, arrange transfer rather than repeatedly prescribing outpatient medicines. A referral should include onset date, cough pattern, vaccination record, specimen type and date, antibiotic exposure, oxygen and feeding status, contacts, pregnancy, infant exposure and notification made. Do not promise admission, free medication or a particular test; identify an actual destination and contingency plan.
Red Flags
Call emergency services or transfer immediately for apnoea, blue or grey colour, severe work of breathing, pauses with bradycardia, oxygen desaturation, exhaustion, reduced consciousness, seizure, shock, inability to feed, repeated aspiration or dehydration. In an infant, a cough with poor feeding or a change in breathing pattern is enough to lower the threshold for hospital review; waiting for a whoop is dangerous.
Pregnancy red flags include respiratory distress, syncope, inability to maintain intake, fever with toxicity and imminent delivery while infectious. The newborn or young infant exposed to a suspected case needs urgent paediatric and public-health advice even if currently well. Do not separate a vulnerable infant from essential care without a workable feeding and safeguarding plan, but reduce exposure and arrange expert help.
In any age group, rapidly worsening cough, focal chest signs, haemoptysis, persistent hypoxaemia, confusion, seizures, severe vomiting, marked weight loss or failure to improve should prompt reassessment for pneumonia, tuberculosis, foreign body or another diagnosis. Isolation failure, inability to complete antibiotics, a household infant, or a healthcare worker caring for neonates is a public-health red flag. Vaccination lowers risk but does not overrule symptoms.
Do not suppress a dangerous cough with sedatives or unverified combination syrups. Escalate the patient, not merely the prescription.
Indian Clinical Context
India’s Universal Immunisation Programme uses pertussis-containing vaccines in childhood schedules, with state and programme details subject to current national guidance. Check the child’s MCP card or digital record, catch up missed doses through the nearest immunisation service, and avoid inventing an alternative schedule when records are uncertain. A private Tdap decision in pregnancy or adolescence should be discussed with an obstetrician or immunisation provider using current Indian recommendations and product availability. WHO’s position paper supports maternal vaccination strategies where adopted nationally, but local policy governs implementation. [WHO 2015]
Suspected pertussis should be communicated to the appropriate district surveillance or public-health team. NCDC identifies pertussis within vaccine-preventable disease surveillance, enabling outbreak detection and response. [NCDC 2026] Do not disclose a family’s diagnosis broadly; share necessary information through lawful, confidential public-health channels. In crowded homes, offer practical ventilation, masking, sleeping separation and caregiving advice rather than an impossible demand for total isolation.
Access barriers matter: PCR may be distant or unaffordable, macrolide supply may vary, and paediatric oxygen or admission may be limited. Give written dosing and emergency advice in the preferred language, confirm who will collect medicines, and document the nearest facility with infant monitoring. Avoid overclaiming that antibiotics will stop the cough, and avoid overuse of antibiotics when the syndrome is not compatible. Public-health work includes vaccination recovery, contact prophylaxis when indicated and respectful stigma-free communication.
NMC Competency Mapping
This guide supports supervised learning in Paediatrics, Medicine, Microbiology, Pharmacology, Community Medicine, Obstetrics and Gynaecology, Emergency Medicine and AETCOM. The learner should recognise age-dependent pertussis presentations, assess severity, select time-appropriate specimens, start safe treatment under supervision, apply isolation and explain why an established cough may persist after antibiotics. Exact competency codes should be confirmed from the current NMC curriculum ledger. [NMC 2024]
An OSCE should test infant observation, oxygen and feeding assessment, exposure history, vaccination review, nasopharyngeal sampling principles and a contact plan. A prescribing station should require weight-based verification, allergy and QT-risk review, pregnancy considerations, completion of therapy and explicit separation of treatment from prophylaxis. A community-medicine station should assess notification, contact tracing, vaccination catch-up and confidentiality.
Professional conduct means not dismissing a vaccinated person, not promising a negative test or immediate cough relief, and not delaying emergency transfer for paperwork. Communicate with parents without blame, obtain consent for information sharing except where public-health law requires it, and make the plan usable at home. The endpoint is early recognition, reduced transmission, equitable referral and safe follow-up, not a memorised antibiotic schedule.
Key Exam Pearls for NEET PG
Pertussis is a toxin-mediated respiratory infection with catarrhal, paroxysmal and convalescent phases. Infants may have apnoea, cyanosis and poor feeding without a whoop; adolescents and adults may present with prolonged paroxysmal cough or post-tussive vomiting. Vaccination does not exclude the diagnosis.
The best specimen is a properly collected nasopharyngeal sample. Culture is more useful early; PCR is sensitive but timing and prior antibiotics affect yield. Treat a strongly suspected case without waiting for a result when the patient or contacts are high risk. Antibiotics reduce infectivity and are most useful early; they do not reliably shorten an established cough, so supportive care and safety-netting remain central. [CDC 2025a; CDC 2025b]
A symptomatic case is generally infectious until five days of effective therapy or the applicable public-health period. CDC supports PEP for household contacts and high-risk people within defined exposure windows, but widespread prophylaxis during community transmission is not automatically beneficial. [CDC 2025d] Infants under 12 months, especially young infants, are the high-risk group.
Exam traps are waiting for a whoop, assuming vaccination rules out pertussis, treating a negative late PCR as definitive, giving sedating cough medicines to infants, and claiming antibiotics rapidly cure the cough. Notification, isolation, vaccination and contact protection are part of the treatment plan.
Frequently Asked Questions
Will antibiotics stop a pertussis cough immediately?
Usually not. Antibiotics are important to treat early disease and reduce transmission, especially around infants and other high-risk people, but the cough can persist because the airways remain irritated. Continue hydration, feeding and breathing observation, complete the prescribed course and return urgently for apnoea, cyanosis, dehydration or deterioration.
When can someone with whooping cough return to school or work?
Follow the local public-health instruction. A common standard is exclusion until five days of effective antibiotic therapy have been completed; untreated infectious periods may be longer. Avoid contact with infants, pregnant people near delivery and vulnerable patients, use respiratory hygiene and arrange notification or contact advice rather than making an informal decision.
Does a vaccinated child or adult still need a pertussis test?
Possibly. Vaccination reduces risk and severity but does not eliminate infection, particularly when immunity has waned. Repeated paroxysms, post-tussive vomiting, exposure, an outbreak or an infant’s apnoea should prompt clinical assessment. Test timing, specimen quality and prior antibiotics affect results, so a late negative PCR may not settle the diagnosis.
What should a household do after exposure to pertussis?
Contact the treating clinician and public-health team promptly, especially if the household includes an infant, pregnant person near term or immunocompromised member. Assess whether post-exposure antibiotics are indicated within the relevant window, check vaccination records, monitor symptoms for 21 days, reduce close contact and seek emergency help for breathing or feeding problems.
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