Whooping Cough Is Back. Babies Are Dying. Why Is This Happening?

Two infants in Kentucky have died in the past year from a disease that no child in the United States should ever die from: pertussis (whooping cough), a disease for which there is a safe, highly effective, and widely available vaccine. According to state officials, both of the infants who died were unvaccinated. So were their mothers. In fact, Kentucky recorded more than 270 cases in the first half of 2025, putting it on track to surpass last year’s total, which was itself the highest in over a decade. 

In this essay, I review what we know about pertussis, why infections are rising, and what, if anything, we can do about it.

What Is Pertussis and Why It Matters 

Pertussis is a bacterial infection caused by Bordetella pertussis. The bacteria has an epidemiology that is somewhat similar to respiratory viruses, like COVID-19 and influenza. People get infected in their upper airways and transmit it to other people through the air. Airborne transmission means that it can spread rapidly through communities. 

The classic symptom is a persistent, hacking cough that can last for weeks to months. In older children and adults, this is extremely uncomfortable and can even lead to rib fractures and fainting. 

In infants, however, the complications are far more severe, because of infants’ smaller airways and immature immune systems. Coughing fits lead to a characteristic gasping breath after a prolonged series of coughs – the “whoop” in “whooping cough.” More worrisome is that these fits can cause vomiting, apnea, and in some cases, pneumonia. Infants may stop breathing and turn blue because they do not have enough oxygen flowing to their lungs. Some, as in the cases in Kentucky, die.

How Do You Treat Pertussis?

Pertussis is one of the few upper respiratory infections for which there is an effective treatment. Physicians prescribe a class of antibiotics known as macrolides—most commonly azithromycin (of the “Z-pack”), clarithromycin, or erythromycin—for 5-14 days, depending on the specific antibiotic prescribed and the patient’s age. Antibiotics can shorten the duration of infectiousness and prevent spread to others. In infants, early treatment may lessen severity, but the benefit declines if treatment is started later in the course of illness.

One of the biggest challenges with treatment, however, is knowing when a patient has pertussis versus a viral infection that does not respond to antibiotics. A person infected with pertussis often looks and sounds as if they have a viral illness at first. They have a stuffy nose, runny nose, mild cough, and low-grade fever. By the time the classic coughing fits begin, it’s often too late for antibiotics to make a meaningful difference in that child’s clinical course. This is especially true for newborns and young infants, who may suddenly become severely ill and require hospitalization for supplemental oxygen and respiratory support.

Because antibiotics only have a minimal impact on shortening the duration of illness and they are often not prescribed early, the only truly effective strategy to reduce severe illness (and deaths) is vaccination before exposure ever occurs.

Why Vaccinating Pregnant Women Saves Lives

One of the most effective ways to protect newborns from pertussis is not to wait until they are born, but to actually vaccinate their mothers during pregnancy. The Tdap vaccine, given between 27 and 36 weeks gestation, stimulates the mother’s immune system to produce antibodies that cross the placenta and protect the baby after birth. This form of “passive immunity” (where antibiotics are transmitted from one person to another) has been part of modern medicine for decades and can be highly effective at preventing infection in newborns.

After children are born, they are recommended the get the pertussis vaccine at five intervals: 2 months, 4 months, 6 months, 15-18 months, and 4-6 years of age. It is usually administered as part of the DTaP vaccine (for diphtheria, tetanus, and acellular pertussis). CDC recommends also adminstering a booster shot, Tdap, at 11-12 years of age.

Yet today, the same forces that have led to a nationwide measles outbreak are impacting pertussis: declines in vaccination rates during and after COVID-19, an emboldened and active anti-vaccine movement, and looser vaccine requirements for school entry and other activities.

According to CDC data, adolescent coverage with the Tdap booster declined from 90% in 2019 to 88% in 2022. In some counties and school districts, particularly in the South and Mountain West, vaccination rates have fallen well below the herd immunity threshold. One challenge with the pertussis vaccine is that protection wanes over time and booster doses, such as the one given just as kids enter their teen years, are essential. (When teens get infected, they spread the infection to others in the community, including young children.)

As a result, CDC “data show that more than six times as many [pertussis] cases were reported in 2024 compared to 2023,” and cases continue to surge in 2025. 

In addition to the usual disinformation directed to parents, pregnant women are increasingly targeted by disinformation campaigns falsely claiming that vaccines are dangerous during pregnancy or unnecessary for newborns. 

The Collapse of Scientific Governance in Vaccine Policy

Unfortunately, what’s making pertussis outbreaks even harder to control is that anti-vaccine forces now have a champion in the U.S. government. In June, Health and Human Services Secretary Robert F. Kennedy, Jr. fired every expert on CDC’s independent vaccine advisory committee, a committee that has reviewed and recommended vaccines in the United States since 1964. Its members review clinical trial data, monitor safety outcomes, and make recommendations that have guided federal and state programs, as well as the decisions of pediatricians and obstetricians around the country. 

If you are not familiar with ACIP, spend a few minutes watching the presentations made during the last meeting of the Biden Administration at https://www.youtube.com/live/gr96tsZnXis. What you see during this October 23, 2024, meeting is detailed, dispassionate reviews of data looking at the basic science, clinical trials, modeling estimates of impact, economic analysis, and the views of patients impacted by these diseases. Perhaps most important there is extensive discussion of safety, including what events might occur, how they have been measured, what their severity is, and whether they warrant changes to a vaccine.

Kennedy has now replaced ACIP experts (and prompted the departures of two CDC officials who prepare data for ACIP) with an odd combination of people of various health-related backgrounds, none of whom have substantial, credible experience in research, clinical practice, or program management of vaccines. These are vaccine skeptics by design, chosen specifically because of their opposition to the public health tools that have averted millions of infections and saved hundreds of thousands of lives over the past century. 

What the Return of Pertussis Tells Us About the Future

The resurgence of pertussis was, sadly, predictable. When vaccination rates fall, the preventable infections most likely to return quickly are those that transmit through the air. Infections that transmit through the air spread faster in a community than other types of infections, because one person can readily infect many other people, including strangers, that they contact in a day. Which is why we first saw outbreaks of measles, then saw pertussis. And why we are likely to see large outbreaks of mumps, rubella, haemophilus influenza type B, and meningococcal infections in the near future as well. 

The narrative circulated by vaccine skeptics and germ deniers is that it’s somehow better to get infected and acquire “natural immunity” than to rely on vaccination. That argument, while superficially appealing, ignores the fact that infection brings suffering, hospitalization, and sometimes death, while vaccination does not.

What You Can Do If You’re a Parent, a Provider, or a Policymaker

If you’re pregnant or planning to become pregnant, ask your doctor about Tdap. If you’ve already had one in a previous pregnancy, you still need one again. That booster dose is needed to provide you baby maximum protection during their period of highest risk (the few months after birth).

If you’re a parent, check your child’s records. Talk to your pediatrician. If they’ve fallen behind, catch up. And if you’re not sure, ask.

If you’re a clinician, have the hard conversations. Speak clearly and compassionately about why these vaccines matter. Don’t assume people already know or that they’ll ask.

And if you’re just a concerned citizen, use your voice (and phone) to restore the integrity of public health governance. Lobby Congressional officials to force the HHS to reconstitute ACIP with actual experts. Lobby your local government to fund state and county health departments and to protect strict school vaccination requirements.