Whooping Cough (Pertussis) in Babies
Content reviewed against published CDC, AAP, WHO guidelines
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Whooping cough (pertussis) is a highly contagious bacterial infection caused by Bordetella pertussis. It causes severe, uncontrollable coughing fits followed by a high-pitched "whoop" sound when breathing in. It is most dangerous in infants under 12 months who are not yet fully vaccinated, and can be life-threatening in newborns.
Key takeaways
- Whooping cough (pertussis) is a highly contagious bacterial infection caused by Bordetella pertussis.
- Duration: Called the "100-day cough" — catarrhal stage (1-2 weeks), paroxysmal stage (2-8 weeks), convalescent stage (weeks to months of gradual improvement). Total duration 6-10 weeks minimum.
- Go to ER if: Baby turns blue or stops breathing during a coughing fit
- A vaccine or immunization is available
Symptoms
How It Presents by Age
0-3 months
May NOT have the classic whoop. Instead may present with apnea (breathing pauses), cyanosis (turning blue), and poor feeding. Coughing fits can be less prominent. This is the highest risk group — hospitalization is almost always needed.
Risk level: Very high — can be fatal
3-6 months
Classic coughing fits with possible whooping. Apnea still possible. Vomiting after coughing common. Most require hospitalization.
Risk level: High
6-12 months
Prolonged coughing fits, often with whooping and post-cough vomiting. May lose weight. Still at significant risk.
Risk level: Moderate to high
1-3 years
Classic whooping cough presentation — paroxysmal cough with whoop. Cough lasts weeks. Known as the "100-day cough" for its prolonged duration.
Risk level: Moderate
Treatment
Antibiotics
Azithromycin is first-line for infants. Treatment shortens the contagious period but may not reduce symptoms if started after the first 1-2 weeks of cough.
Hospital monitoring
Infants under 4 months are almost always hospitalized for monitoring of apnea, oxygen levels, and feeding.
Supportive care
Gentle suctioning, oxygen if needed, IV fluids if unable to feed. Cough suppressants do NOT help and should not be used.
Prophylaxis for contacts
All close household contacts should receive antibiotics regardless of vaccination status to prevent spread.
Home Care
- Keep environment calm and quiet (stimulation can trigger coughing fits)
- Offer small, frequent meals to reduce vomiting
- Keep baby away from irritants — smoke, dust, chemical fumes
- Use a cool-mist humidifier
- Feed shortly after a coughing fit when the child is calm
- Stay upright or elevate head during and after feeding
- Keep baby hydrated with frequent small feeds
When to Worry
Go to the ER if:
- Baby turns blue or stops breathing during a coughing fit
- Apnea (breathing pauses) lasting more than a few seconds
- Severe breathing difficulty between coughing fits
- Baby under 3 months with suspected whooping cough
- Seizure
- Baby unable to keep any feeds down
- Extreme lethargy or unresponsiveness between fits
Call your doctor if:
- Any suspicion of whooping cough (persistent cough for 2+ weeks, worse at night)
- Exposure to a confirmed pertussis case
- Baby is not gaining weight due to vomiting
- Cough is disrupting sleep significantly
- You want to discuss prophylactic antibiotics for family members
Keep an eye on:
- Coughing fits are becoming more frequent or severe
- Baby turns blue or very red during coughing
- Pauses in breathing after coughing
- Baby is vomiting after most feeds
- Weight loss or failure to gain weight
Prevention
- DTaP vaccine series starting at 2 months (5-dose series)
- Tdap booster for all pregnant women during each pregnancy (weeks 27-36) to pass antibodies to baby
- Tdap for all caregivers and close contacts (cocooning strategy)
- Keep unvaccinated infants away from anyone with a cough
- Complete the full vaccination series on schedule
- Tdap booster for adolescents and adults every 10 years
Contagion & Incubation
Incubation
5-10 days (range 4-21 days)
Contagious for
From the start of symptoms through at least 2 weeks after cough onset, or until 5 days after starting appropriate antibiotics
Duration
Called the "100-day cough" — catarrhal stage (1-2 weeks), paroxysmal stage (2-8 weeks), convalescent stage (weeks to months of gradual improvement). Total duration 6-10 weeks minimum.
Frequently asked questions
How long does whooping cough (pertussis) last?
How does pertussis spread?
When should I take my baby to the ER?
Can pertussis be prevented?
When can my child return to daycare?
Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Illnesses
Bottom line
Whooping Cough (Pertussis) is treatable with appropriate medical care. Seek emergency care if baby turns blue or stops breathing during a coughing fit.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.