What is pertussis and why is it called whooping cough?

Pertussis is a bacterial infection that causes severe, uncontrollable coughing fits. It's called 'whooping cough' because of the characteristic 'whoop' sound people make when gasping for air between coughs. In infants, the disease can be life-threatening, causing apnea (stopped breathing) without the classic whoop.

How does pertussis spread?

Pertussis spreads through respiratory droplets when an infected person coughs or sneezes. It's extremely contagious - people with pertussis typically infect 12-17 close contacts. You can spread the disease from early infection stages, often before you even know you're sick.

What are the stages of pertussis?

Pertussis has three stages: 1) Catarrhal stage (1-2 weeks): mild cold-like symptoms. 2) Paroxysmal stage (1-6 weeks): severe coughing fits with the 'whoop' sound, vomiting after coughing. 3) Convalescent stage (weeks to months): gradual recovery, though coughing can persist for months.

Is the pertussis vaccine effective?

Yes, the DTaP vaccine (for children) and Tdap booster (for adolescents and adults) are effective at preventing pertussis. However, immunity wanes over time, which is why boosters are recommended. Vaccinated people who do get infected typically have much milder symptoms and are less likely to spread the disease.

Why are pertussis cases increasing?

Pertussis cases fluctuate in 3-5 year cycles, and waning immunity from childhood vaccination contributes to adult cases. Increased awareness and better diagnostic testing also reveal more cases. Vaccination remains the best protection, especially for pregnant women to protect newborns.

Where are pertussis outbreaks occurring?

Pertussis outbreaks can occur anywhere, often in schools and communities with lower vaccination rates. Check the live outbreak data above for current pertussis activity in your region.

Illinois

Pertussis in Illinois

Pertussis, also known as whooping cough, is a highly contagious respiratory disease caused by the bacterium Bordetella pertussis. It causes severe coughing fits that can last for weeks or months. Track Pertussis activity and outbreaks specific to Illinois.

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What is Pertussis?

Pertussis, commonly known as whooping cough, gets its name from the distinctive 'whooping' sound made when gasping for air after a coughing fit. Before the vaccine was developed, pertussis was a leading cause of childhood death worldwide. Today, it remains a serious threat, especially to infants who are too young to be fully vaccinated.

Symptoms

Initial cold-like symptoms (runny nose, mild fever)
Severe, uncontrollable coughing fits
Whooping sound when gasping for air
Vomiting after coughing
Exhaustion after coughing fits
Apnea (pauses in breathing) in infants

Transmission

Pertussis spreads through respiratory droplets when an infected person coughs or sneezes. It is highly contagious, especially in the first two weeks when symptoms resemble a common cold. Close contact with infected individuals poses the highest risk.

Contagious Period: From early cold-like symptoms through 3 weeks after coughing begins (or 5 days after starting antibiotics)

Prevention

DTaP vaccine for infants and children (5 doses by age 6)
Tdap booster for adolescents (age 11-12) and adults
Tdap during each pregnancy (27-36 weeks) to protect newborns
Isolation of infected individuals
Prophylactic antibiotics for close contacts
Practice respiratory hygiene and handwashing

Illinois Health Resources

Local health department information and state-specific prevention guidance

We're Monitoring Illinois

Our AI-powered surveillance continuously monitors Pertussis activity across Illinois. We track data from state health departments, local hospitals, CDC reports, and 50+ global health sources to provide early warning of emerging threats.

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Illinois Health Department

For official state health alerts, vaccination locations, and public health guidance specific to Illinois, visit your state health department's website.

→ Illinois Department of Health → Find Pertussis Vaccination Near You → CDC Travel Health Notices

Protecting Yourself in Illinois

Whether you live in Illinois, are traveling there, or have family in the state, understanding Pertussis prevention is essential. Follow these evidence-based prevention measures:

Prevention Measures

DTaP vaccine for infants and children (5 doses by age 6)
Tdap booster for adolescents (age 11-12) and adults
Tdap during each pregnancy (27-36 weeks) to protect newborns
Isolation of infected individuals
Prophylactic antibiotics for close contacts
Practice respiratory hygiene and handwashing

When to Seek Care

If you experience symptoms of Pertussis in Illinois, contact your healthcare provider immediately. Early diagnosis and treatment improve outcomes significantly.

Emergency symptoms: If you experience severe symptoms, difficulty breathing, or signs of dehydration, call 911 or go to your nearest emergency room.

Expert Resources & References

Trusted information from leading health organizations

CDC

Official guidance from the U.S. Centers for Disease Control and Prevention

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WHO

Global disease surveillance and guidelines from the World Health Organization

View WHO Resources →

Research

Latest peer-reviewed research and clinical studies

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Medically Reviewed Content

Disease information on Virus Watcher is reviewed by our Chief Epidemiologist, a former CDC lead analyst for FluSight forecasting. Outbreak data is aggregated from verified sources including BEACON, ProMED, WHO, CDC, and 50+ national health agencies. This information is for educational purposes and should not replace professional medical advice.

Last reviewed: 2026-03-04

Frequently Asked Questions

Common questions about Pertussis answered by our epidemiology team

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