Whooping Cough (Pertussis): Why Vaccination Still Matters

Overview

Whooping cough (pertussis) is a bacterial infection caused by Bordetella pertussis. It spreads easily through coughing and sneezing and is most dangerous for infants and young children.

Before vaccines, pertussis epidemics were common and caused thousands of deaths each year in the U.S. While vaccination dramatically reduced the burden of disease, outbreaks have returned in communities with low coverage or waning immunity.

Key Points

Pertussis causes severe coughing fits, often followed by a characteristic “whoop” sound when breathing in.
Infants under 12 months are at highest risk of hospitalization, complications, and death.
Vaccination (DTaP in children, Tdap boosters in adolescents and adults) is the best protection.
Outbreaks occur when vaccination rates decline or booster coverage is missed.

Symptoms

Symptoms usually develop 5–10 days after exposure but can take up to 3 weeks:

Mild cough, runny nose, low-grade fever (early stage, “catarrhal stage”).
Progression to severe, prolonged coughing fits, sometimes followed by vomiting or exhaustion (“paroxysmal stage”).
The “whoop” sound when inhaling is more common in children than adults.
Symptoms can persist for 6 weeks or more, giving the nickname “the 100-day cough.”

Complications

Pertussis can be life-threatening, particularly in infants:

Apnea (pauses in breathing)
Pneumonia
Seizures
Brain damage from lack of oxygen
Death (most common in babies under 6 months)

In older children and adults, complications may include rib fractures from coughing or hernias.

Prevention

DTaP vaccine (diphtheria, tetanus, acellular pertussis):
- Series of 5 shots given at 2, 4, 6, 15–18 months, and 4–6 years.
Tdap booster:
- One dose recommended at 11–12 years.
- Adults should receive at least one Tdap, then Td or Tdap every 10 years.
Pregnancy: Tdap is recommended during each pregnancy (preferably in the third trimester) to pass antibodies to newborns.
Cocooning strategy: Vaccinating parents, siblings, and caregivers to protect infants too young to be fully vaccinated.

Recent Outbreaks

Pertussis has re-emerged in several states. In 2025, Louisiana reported over 170 cases by May, surpassing the total number for 2024.
These outbreaks highlight the importance of booster doses and community-wide vaccination coverage.

FAQ

Q: Why do outbreaks still happen if vaccines exist?
A: Immunity from the vaccine can wane over time, and low coverage allows the bacteria to spread. Boosters are essential.

Q: Can adults get pertussis?
A: Yes. Adults often have milder symptoms but can still transmit the disease to infants.

Q: Is the vaccine safe?
A: Yes. Side effects are usually mild (soreness, low fever). Serious reactions are extremely rare.

Q: Why is pertussis more severe in babies?
A: Infants have smaller airways and weaker immune systems, making them especially vulnerable to complications.

Further Reading