Whooping cough, also called pertussis, is a highly contagious infection that affects the airways and breathing. It is known for causing severe, repeated coughing fits that can last for weeks or even months. A classic sign is a “whoop” sound when a person breathes in after a long coughing fit, but not everyone with the illness will have this sound.

Although most people recover from whooping cough, babies and young children are at risk for severe symptoms and complications and may require hospitalization. Infants younger than one year are at the greatest risk for severe illness and even death caused by the infection.

In the United States, the number of whooping cough cases dropped sharply after the introduction of the vaccine in the 1940s. However, cases have increased in recent years, with more than 35,000 reported cases nationwide in 2024, six times as many cases reported in 2023.

Early diagnosis and treatment, along with vaccination, help prevent serious problems and protect those most at risk for whooping cough and its complications.

Whooping cough is a serious infection of the breathing passages caused by the Bordetella pertussis bacteria. This infection leads to swelling and irritation in the tubes that carry air to and from the lungs. The body responds with violent coughing fits as it tries to clear the airways.

Whooping cough can affect people of all ages, but it is most dangerous for babies and young children, especially those who have not received recommended vaccines. Older children, teens, and adults can also get whooping cough, even if vaccinated, but their symptoms are often less severe.

The illness typically develops in three stages. The first stage, called the catarrhal stage, resembles a common cold. The second stage, known as the paroxysmal stage, is when severe coughing fits begin. The third stage, called the convalescent stage, is when the cough gradually improves, but recovery can take weeks or even months.

If not prevented or treated early, whooping cough can lead to complications and even death, especially in infants.

Whooping cough is an infection caused by the Bordetella pertussis bacteria, which spreads easily through the air. When a person with whooping cough coughs or sneezes, tiny droplets containing the bacteria are released and can be inhaled by others nearby. The infection is highly contagious, especially in the early stages before the cough becomes severe.

Normally, the airways are lined with tiny hair-like structures called cilia, which help move mucus and particles out of the lungs. In whooping cough, the bacteria attach to these cilia and release toxins (poisons) that damage them and cause swelling. This makes it harder for the body to clear mucus, which can cause severe, persistent cough and serious breathing problems.

Before the pertussis vaccine became widely available in the 1940s, more than 200,000 people in the U.S. contracted the infection each year, and whooping cough was a common cause of illness and death, especially in infants. After the introduction of the vaccine, incidence decreased by 75 percent in the U.S. However, in recent years, rates of whooping cough have started to rise again.

Immunity to whooping cough, whether from vaccination or from having had the disease, decreases over time. This means that even people who have been vaccinated or who have had whooping cough in the past can get it again, although their illness is usually milder.

Anyone who is exposed to the Bordetella pertussis bacteria is at risk for whooping cough. However, certain people are more susceptible to more severe symptoms and complications, including:

• Babies younger than one year old
• People who are not vaccinated
• Pregnant women
• People with a weakened immune system or who have certain health conditions, such as moderate to severe asthma

Nearly three-quarters of reported whooping cough cases occur in children younger than 5, and more than one-third are infants less than 6 months old before they are fully vaccinated. Getting vaccinated in the third trimester of pregnancy helps protect babies from the infection and its potentially life-threatening complications.

During the first stage of the infection, symptoms of whooping cough resemble those of the common cold. In the later stage, symptoms can become more serious. Babies and young children may not have the classic “whoop” sound. Instead, they may have pauses in breathing, turn blue, or lose appetite. In some cases, the only sign in infants may be difficulty breathing.

Early symptoms (first one to two weeks):

• Runny or stuffy nose
• Mild, occasional cough
• Low-grade fever (less than 100.4°F)
• Red, watery eyes
• Sneezing
• Fatigue

Later symptoms (after one to two weeks):

• Severe, rapid, and repeated coughing fits with periods of feeling well between fits
• High-pitched “whoop” sound when breathing in (more common in children between six months and 5 years old)
• Vomiting from forceful coughing
• Feeling very tired after coughing fits
• Difficulty breathing or pauses in breathing, especially in babies under 6 months
• Turning blue or dusky during coughing fits
• Trouble sleeping due to coughing
• Rib pain or even rib fractures from severe coughing
• Loss of appetite or poor feeding (especially in infants)
• Gagging or gasping for air (more common in infants)
• Seizures (rare, more common in infants)
• Fainting after coughing

Other possible symptoms and signs:

• Dehydration from vomiting or poor feeding
• Weight loss due to ongoing illness
• Ear infections
• Bleeding under the skin or in the eyes from forceful coughing
• Hernias or rectal prolapse (bulging of tissue) from severe coughing

Typically, to diagnose whooping cough, a doctor will review a patient’s medical history, conduct a physical exam, and order one or more diagnostic tests.

A doctor may ask about symptoms, the duration of coughing, vaccination history, and contact with people with whooping cough. During the physical exam, the doctor will listen to the lungs, check for signs of breathing difficulty, and ask about other symptoms such as vomiting after coughing or turning blue during coughing fits.

Additional tests may be necessary, including:

• Nasopharyngeal swab or aspirate: A sample is taken from the back of the nose or throat to test for the presence of the Bordetella pertussis bacteria. This is usually done with a long swab or by gently suctioning fluid. Depending on the circumstances, the specimen will be evaluated one of two ways.
• Bacteria culture: The sample is grown in a lab to see if the bacteria are present. This test is most accurate in the first two weeks after coughing begins, but results can take several days.
• Polymerase chain reaction (PCR) test: This test looks for genetic material from the bacteria in the sample. It is more sensitive than culture and can give results in a few hours.
• Blood test for antibodies: Sometimes, in later stages of illness, doctors may order a blood test to look for the body’s response to infection, but this is not usually the main test for diagnosis.

If the diagnosis is unclear or if symptoms are not improving, a doctor may order a chest X-ray to look for signs of pneumonia or other lung problems. However, imaging tests are not usually needed to diagnose whooping cough.

A doctor will use symptoms, test results, and possible exposure history to make a diagnosis. Early diagnosis is important, as this can help prevent spreading the infection to others, especially babies and people at high risk.

Whooping cough is treated with antibiotics and supportive care. Early treatment is important to help reduce the severity of the illness and prevent spreading it to others. Most people with whooping cough can be cared for at home, but young children and people with underlying conditions may require treatment in the hospital.

Main treatments include:

• Antibiotics: Antibiotics work best when started early, before severe coughing fits begin. They also help prevent the spread of the infection to others. Erythromycin, azithromycin, or clarithromycin are the most common antibiotics used for whooping cough.
• Supportive care: It is important to keep the airways clear, make sure the person gets enough fluids, and provide oxygen if needed. Babies and people with severe symptoms may need treatment in the hospital where care may include monitoring breathing, suctioning mucus as necessary, and providing fluids intravenously.
• Isolation: To prevent spread to others, people with whooping cough should stay away from others, especially babies and those at high risk for complications, until they are no longer contagious (usually after five days of antibiotics or three weeks after coughing starts).
• Preventive antibiotics for close contacts: People who live with or have close contact with someone with whooping cough may be given antibiotics to help prevent them from getting sick. This is especially important for babies, pregnant women, and people with weakened immune systems.

During the recovery stage of the illness, the cough may linger or recur. It is important to avoid things that can cause coughing or make it worse, such as smoke, dust, or strong smells. Using a cool mist humidifier can help soothe the cough and loosen mucus. Eating small, frequent meals and drinking plenty of fluids can help prevent vomiting and dehydration from a severe, recurrent cough.

Cough medicines are usually not helpful for whooping cough and are not recommended for young children. A health care provider should always be consulted before giving any medicine for cough.

People with whooping cough may be at increased risk for certain serious complications, including:

• Pneumonia: Serious, dangerous infection of the lungs, most common in babies and young children
• Apnea: Life-threatening pauses in breathing, most common in infants
• Seizures: Uncontrolled shaking, more likely in young children
• Encephalopathy: Brain disease or injury, which can cause long-term problems
• Dehydration: Loss of fluids from vomiting or poor feeding
• Rib fractures: Broken ribs from severe coughing
• Fainting: Passing out after coughing fits
• Weight loss: Due to poor feeding or vomiting
• Ear infections: Infection of the middle ear
• Hernias or rectal prolapse: Bulging of tissue due to forceful coughing
• Bleeding under the skin or in the eyes: Caused by pressure from coughing
• Death: Most often in babies younger than one year old

Other possible complications include nosebleeds, hernias, and, rarely, high blood pressure in the lungs (pulmonary hypertension), which can be very serious in infants. Complications are more common and more severe in babies, especially those who are too young to be fully vaccinated.

The outlook for people with whooping cough depends on several factors, including age, overall health, vaccination status, and the timeliness of treatment. People who develop symptoms of whooping cough, especially a severe or persistent cough, should be evaluated by a health care provider. Early treatment can make a difference and help prevent the spread of this serious illness.

Most people with whooping cough recover completely, although the illness can be very uncomfortable and disruptive. The cough may linger for a long time, and coughing fits can return with other respiratory infections for months after the initial illness. Vaccination, early diagnosis, and prompt treatment are the best ways to improve the outlook and prevent serious problems.

Babies younger than one year, especially those who have not had all their vaccines, are at the highest risk for severe illness, complications, and death. Older children, teens, and adults usually recover fully, but the cough can last for weeks or even months.

Vaccination is the most effective way to protect against the disease and its complications, especially for those most at risk. Babies who are too young to be vaccinated are best protected when people around them are vaccinated.