Why Are Whooping Cough Cases Rising? What to Know and How to Avoid It

Cases of whooping cough (pertussis) have surged, in the Philadelphia region and across the U.S. as well. According to the Centers for Disease Control and Prevention (CDC), more than 17,500 pertussis cases have been reported in the U.S. so far in 2024, compared with only 3,962 cases for all of 2023.  That’s an increase of more than 340% – and physicians believe these numbers represent a fraction of the total cases, since many people who get sick are not tested for the disease.

Why have cases of whooping cough increased? 

For one thing, it’s extremely contagious. Whooping cough is caused by the Bordetella pertussis bacterium and spreads through droplets when infected people cough and sneeze. The CDC estimates that about 80% of people with no immunity will get whooping cough if exposed to an infected person.  

Another factor is decreased immunity in older kids and adults. Although infants are vaccinated starting at two months old against pertussis with the DTaP vaccine – the first in a series of shots given during childhood – immunity fades over time. The farther you are from your last vaccine or booster, the more likely you are to contract whooping cough if exposed. 

“Healthy older children and adults may not get very sick with whooping cough, but they’re typically the ones who infect those who develop severe disease, including newborns and people with lung problems and weak immune systems,” says Ericka Hayes, MD, Senior Medical Director of Infection Prevention at Children's Hospital of Philadelphia (CHOP). “For newborns specifically, it’s extremely important that pregnant individuals get a whooping cough (TDaP) booster with every pregnancy. This allows their baby to be born with the lifesaving antibodies that protect them from whooping cough immediately.” 

What are the symptoms of whooping cough?

Whooping cough usually first appears as a “regular” cold. It develops over one to three weeks, with initial mild cold symptoms evolving into persistent, sometimes severe, cough that’s often accompanied by vomiting. Very young infants often do not develop a severe cough – instead they show difficulty feeding and can stop breathing. A diagnosis is confirmed either by testing secretions from the nose or throat or blood testing for antibodies. Consult our condition page for whooping cough for details on specific symptoms. 

What’s the difference between a “normal” cough and whooping cough? 

Whooping cough is named for the “whoop” sound a patient makes when struggling to inhale through an airway constricted by mucus. Bouts of uncontrollable coughing can last for weeks or months, and at times get so severe that they cause vomiting, nosebleeds, cracked ribs or even hernias. Infants may not make the whooping sound but may struggle to catch their breath or experience short periods where no air is moving from the mouth or nose into the lungs (apnea). 

How is whooping cough treated? 

Specific treatment for whooping cough will depend on your child’s age, health and medical history. Typically, your doctor will prescribe azithromycin (Zithromax®) or a related antibiotic. In some severe cases, your child may be hospitalized for monitoring, supported with oxygen and intravenous (IV) fluids until they begin to recover. Our condition page for whooping cough has more details about when to seek medical attention for your child. 

How can we prevent the spread of whooping cough?  

Infants and young children already have smaller, narrower windpipes, so a disease that constricts their airways can be dangerous, even fatal. Here are the best ways to prevent the spread of whooping cough. 

• Stay vaccinated and boosted. Because most children contract whooping cough from adults, it’s important for both adults and children to stay current with their pertussis vaccines and boosters. The DTaP vaccine is administered to infants and children in 5 stages: at 2 months, 4 months, 6 months, 15 to 18 months and again between 4 and 6 years old. The TDaP vaccine is given to children 11 and older. More information on these vaccines is available at the CHOP Vaccine Education Center. 
• Pregnant women can get a single dose of TDaP vaccine between 27 and 36 weeks’ gestation to boost the level of pertussis antibodies in their blood. This will protect their newborn babies if they are exposed to the disease before being vaccinated.  
• If your child is sick, keep them home from school. 
• If your child is diagnosed with pertussis, they should be isolated with the door closed. After Day 5 of antibiotics, they will no longer be contagious. Other household members should consult their physician for preventive treatment (prophylaxis) to prevent them from getting pertussis. 
• If you or your child has been exposed to pertussis, wear masks around others. If anyone in your household starts to show symptoms after exposure, ask to be tested.