Updated on September 26, 2024.
In the U.S., the number of people with pertussis—also known as whooping cough—is increasing. This very contagious respiratory illness is caused by a type of bacteria called Bordetella pertussis. At first, the infection may seem just like a cold. But unlike the common cold, which is caused by viruses, whooping cough can lead to intense and uncontrolled coughing fits that last for weeks or months.
People often make a whoop-like sound when they gasp for air during a coughing fit, which is how pertussis got its nickname. For some, these bouts of coughing can make it hard to breathe or sleep. Some people may vomit or even break a rib.
People with whooping cough are contagious as soon as their symptoms appear. Early on, they may be very mild. So, people could unknowingly spread the infection to others. Then after the coughing begins, those who are infected may remain contagious for up to three more weeks.
As of September 2024, there have been 14,569 confirmed whooping cough cases in the United States—the highest number of cases since 2014. By comparison, by this point in 2023, there were only 3,475 confirmed infections, according to the Centers for Disease Control and Prevention (CDC).
What is driving this worrisome trend? And how can you avoid infection?
Whooping cough outbreaks and vaccine timeline
There has been a vaccine to prevent whooping cough for more than 100 years. Back in the 1920’s and 30s, anywhere from about 100,000 to more than 265,000 people got whooping cough each year. In the decades that followed, annual cases fell from highs of around 60,000 in the 1950s to lows of about 2,000 in the 1980s.
But once whooping cough was seemingly a thing of the past, people were less worried about the infection—and more worried about the vaccine due to fears about rare but serious side effects.
So, in 1991, an updated vaccine was introduced. It was based on a different technology that causes fewer and milder side effects, such as redness or soreness at the injection site, mild fever, headache, and tiredness. It is the vaccine currently used to routinely vaccinate kids and adults in the United States against pertussis—as well as diphtheria and tetanus. There are two versions of this vaccine, depending on how old you are:
DTaP: This vaccine is given to infants and young children. They receive five doses at the following ages:
- Dose 1: 2 months old
- Dose 2: 4 months old
- Dose 3: 6 months old
- Dose 4: Between 15 and 18 months old
- Dose 5: Between 4 and 6 years old
Tdap: This vaccine is given to older children and adults, usually starting at age 11 or 12. Pregnant people should also get this vaccine between the 27th and 36th week of pregnancy. Since this is a booster shot it contains lower doses of the diphtheria and pertussis vaccines.
But protection from this updated vaccine declines over time. People need a Tdap booster every 10 years to maintain their immunity.
By the late 1990s, infections started to creep back up to about 7,000 per year and settled around 10,000 infections each year in 2002 and 2003. But starting in 2004, (likely when protection from the shots people got in the early 1990s waned), annual infections surged again, peaking in 2012 at 48,277 cases.
During the COVID pandemic, whooping cough cases fell to very low rates not seen since the 1980s due to masking, physical distancing, and other infection control measures that were in place. But as of 2024, whopping cough cases are returning to pre-pandemic levels.
Vaccine hesitancy also plays a role in outbreaks
Complicating matters, in the U.S. (and other parts of the world) the number of people hesitating or refusing to vaccinate is growing. In November 2023, the CDC reported the highest childhood vaccine exemption rate ever in the United States. During the 2022–23 school year, the exemption rate increased 0.4 percentage points to 3 percent. Exemptions (a medical, religious, or philosophical reason that prevents a person from receiving a vaccine) increased in 41 states. Exemptions also exceeded 5 percent in 10 states, which increases the risk for outbreaks of vaccine-preventable diseases.
In 2022-2023, coverage remained near 93 percent for all reported vaccines, including 92.7 percent for DTaP. Between 90 and 95 percent of the population must be vaccinated against whooping cough to effectively stop the infection from spreading.
Spot the symptoms of whooping cough
Anyone can get whooping cough. The infection goes through three stages, starting with a mild cough and low-grade fever.
It can be difficult to detect, since the symptoms are very similar to that of the common cold or flu. This initial stage can also involve a runny nose and trouble breathing. In this beginning stage, the infection is very contagious.
Once it progresses to the second stage people develop repeated, rapid coughing fits that may trigger vomiting and lead to exhaustion. Frequent coughing followed by the “whooping” sound develops as the infection progresses. Some people don’t make the whoop-like sound. They may just have a persistent cough.
During the final stage, people gradually begin to recover. The coughing fits become less frequent over the course of two to three weeks. For some people, the intense bouts of coughing may come back even months later. During the recovery stage, people may also be more susceptible to other respiratory infections since their immune system may be weakened.
In certain cases, whooping cough can also lead to complications, such as:
- Dehydration
- Trouble sleeping
- Fainting
- Weight loss
- Urinary incontinence, nosebleeds, or hernia (due to intense coughing fits)
- Middle ear infection
Other more severe complications of whooping cough can also include:
- Pneumonia
- Collapsed lung
- Broken rib
- Rectal prolapse (the rectum protrudes from the anus)
- Seizures
- Subdural hematomas (blood pools between the brain and the skull)
- Encephalopathy (resulting from a lack of oxygen due to coughing or the bacteria)
- Apnea (breathing pauses due to poor airflow)
- Death
Whooping cough can be particularly dangerous for babies since they have tiny airways that can swell easily, blocking airflow. About half of all infants who are infected need to be hospitalized.
How is whooping cough treated?
The best way to manage whooping cough is to prevent the infection in the first place. Being up to date on your vaccines is critical. If you are unsure if or when you or your children received your last TDaP or Dtap shot, speak to your healthcare provider (HCP) about when to get a dose of this vaccine.
Anyone who thinks they may have been exposed to whooping cough or have the infection should see their HCP. There are blood and mucus tests which can screen for the condition.
For those who do become infected, treatment with antibiotics, such as azithromycin and erythromycin, can help. But treatment with antibiotics is most effective in the first two weeks. These drugs are less helpful once someone has had whooping cough for three weeks or more. Always take antibiotics exactly as prescribed. Do not stop taking them until they are finished—even if you start to feel better.
Other ways to help support recovery from whooping cough:
- Rest.
- Drink plenty of fluids to prevent dehydration.
- Use a cool-mist humidifier to help you breathe easier.
- Do not take over-the-counter cough remedies without asking your HCP about it first.
- Avoid smoke, dust, and other irritants that could trigger a coughing fit.
