Cases have quadrupled compared to this time last year and declining vaccination rates are driving the increase across the country.
Whooping cough is making a return that public health officials had hoped to avoid. The highly contagious bacterial infection, known medically as pertussis, has surged to roughly 16,375 reported cases across the United States as of 2024, compared to approximately 3,771 cases at the same point the previous year. States including Pennsylvania and Illinois are seeing particularly elevated infection rates.
The primary driver behind the increase is not a change in the bacteria itself. It is a decline in vaccination uptake.
What whooping cough actually does to the body
Pertussis is a respiratory infection caused by bacteria that release toxins irritating the airways, triggering severe coughing fits that can be violent enough to crack ribs. The distinctive sound that gives the illness its common name comes from the sharp intake of breath following each coughing episode, a high-pitched whoop that signals the airways are struggling to recover between attacks.
Early symptoms are deceptively mild. The initial stage, which lasts one to two weeks, resembles a common cold with a runny nose and light cough. The illness becomes more recognizable in its second phase, when the coughing attacks intensify and can be accompanied by vomiting and exhaustion. Recovery, the third stage, can stretch across two to three weeks of gradual improvement, but a residual cough often lingers for months afterward. In some cultures the illness is called the 100-day cough, a name that reflects how long it can take to fully clear.
Other symptoms throughout the illness include fever, fatigue, difficulty sleeping, and trouble breathing.
Who is most at risk
Whooping cough can affect anyone who is unprotected, but the stakes are highest for infants. Babies are too young to be fully vaccinated and do not yet have immune systems capable of managing the infection on their own. Fatalities in infants have been reported this year. Adults with compromised immune systems also face elevated risk, though deaths in otherwise healthy adults are uncommon. For most adults the illness presents as severe and prolonged rather than life-threatening, but its duration and intensity can be significantly disabling.
The disease spreads easily through respiratory droplets, meaning close contact with an infected person, including in households and schools, creates significant transmission risk.
The vaccination picture and why it matters
The CDC recommends the DTaP vaccine for children under six and the Tdap vaccine for those 11 and older. The schedule runs from infancy through early adolescence and includes a dose during pregnancy between weeks 27 and 36 to transfer some protection to newborns before they can be vaccinated themselves. Adults are advised to receive a booster every 10 years, but many do not.
That gap in adult boosters is part of what experts point to when explaining the current surge. The vaccine is not 100% effective, but vaccinated individuals who do contract the illness typically experience significantly milder symptoms. Lower vaccination rates across a population reduce the collective barrier against transmission and allow the infection to spread more easily among those with no protection at all.
What to do if symptoms appear
Anyone experiencing prolonged or severe cough, especially accompanied by a whooping sound on inhalation, should seek medical attention promptly. Testing can confirm a pertussis diagnosis. Antibiotics are most effective when given early in the illness, ideally before the most intense symptoms develop, and they also reduce the risk of passing the infection to others.
For those already in the thick of the illness, supportive care helps manage symptoms. Using a humidifier can ease coughing, eating small and frequent meals reduces the risk of vomiting, and staying hydrated is important throughout the recovery period. Avoiding contact with infants and other vulnerable individuals while infectious is a meaningful step in limiting spread.
The simplest and most effective protection remains staying current with vaccinations. That means adults checking when their last Tdap booster was, and parents ensuring their children are following the recommended schedule without gaps.
