Whooping Cough (Pertussis): How It Spreads, Who Is Most at Risk, Prevention and Treatment

Whooping cough, also called pertussis, is a very contagious respiratory illness. It can start like a common cold, but unlike a cold its coughing can last for weeks or months. Treating it early with antibiotics may make the infection less serious.

What it is

Whooping cough is caused by a bacterium, Bordetella pertussis, which is found only in humans.

The bacteria attach to the cilia — tiny, hair-like extensions lining part of the upper respiratory system — and release toxins that damage the cilia and make the airways swell.

A computer-generated image of Bordetella pertussis. Image from CDC's page.

How common it is

Whooping cough is endemic (common) in the United States, with peaks in reported cases every few years. Public health staff can follow the numbers on CDC's surveillance and trends page.

Symptoms

Symptoms vary with age and with whether someone has been vaccinated. CDC describes them in Symptoms of Whooping Cough.

Who is most at risk

Age and underlying medical conditions raise the risk of a severe case, which makes protecting these people especially important.

• Babies under 1 year are at the greatest risk of catching whooping cough and of severe complications.
• People whose existing health conditions could be worsened by it are at high risk of severe infection. Such conditions include, among others:
• • immunocompromising conditions;
  • moderate to severe asthma that is treated with medicine.

How it spreads

The bacteria pass easily from person to person through the air: a person with whooping cough coughs or sneezes out small particles carrying them, and others breathe them in. Spread is likeliest when people spend a lot of time together or share breathing space.

• Contagious for weeks: from the start of symptoms until at least 2 weeks after coughing begins. Antibiotics taken early may shorten that time.
• Spread without knowing: some people have mild symptoms and don't realize they have it, yet can still pass it on. Many babies who get whooping cough catch it from older siblings, parents or caregivers who don't know they are sick.

Prevention

CDC recommends whooping cough vaccination for everyone. Illustration from CDC's page.

• Vaccination is the best way to prevent whooping cough, and CDC recommends it for everyone. See Whooping Cough Vaccination.
• Preventive antibiotics — postexposure antimicrobial prophylaxis (PEP) — are given to someone exposed to the bacteria to keep them from getting sick. Some people should have them after being around someone with whooping cough. If you've been exposed, talk to a healthcare provider; a provider or the health department usually decides who gets them. Guidance for public health: Postexposure Antimicrobial Prophylaxis.
• Good hygiene helps stop many respiratory illnesses: handwashing and covering coughs and sneezes.

Having had it is not enough. People who have had whooping cough have some immunity, but it doesn't last a lifetime.

When it is spreading widely in a community, public health authorities concentrate on the people at highest risk of serious illness — vaccination and preventive antibiotics for them and for the people around them — and, second, on protecting everyone else.

Diagnosis

Whooping cough can be hard to diagnose, because its signs and symptoms look like other respiratory illnesses. It helps to know whether you've been in contact with someone who has it. Healthcare providers diagnose it from:

• a history of typical signs and symptoms;
• a physical exam;
• a lab test of a mucus sample from the back of the throat;
• a blood test.

Treatment

It is very important to treat whooping cough early — before the coughing fits begin. Providers generally treat it with antibiotics; serious cases may need hospital care. More: Treatment of Whooping Cough.

CDC also offers posters, fact sheets and videos about whooping cough.

Sources

Based on "About Whooping Cough," Centers for Disease Control and Prevention; a work of the United States government in the public domain. The source's stock photograph of a mother and baby is not reproduced.