Dr. Joshua Sharfstein: Whooping cough
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Dr. Sharfstein also conducted an interview on this topic in Spanish.
The U.S. has recorded more than 8,000 cases of whooping cough, also called pertussis, in 2025, which is twice the number of cases reported by this time last year.
On May 16, 2025, SciLine interviewed: Dr. Joshua Sharfstein, a pediatrician and distinguished professor of the practice at the Johns Hopkins Bloomberg School of Public Health. He was former health commissioner for Baltimore City and former health secretary for the state of Maryland.
See the footage and transcript from the interview below, or select ‘Contents’ on the left to skip to specific questions.
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Introduction
[0:00:19]
JOSHUA SHARFSTEIN: Hi, I’m Josh Sharfstein. I am a distinguished professor of the practice in Health Policy and Management here at the Johns Hopkins Bloomberg School of Public Health, and I study vaccine policy and other topics in public health.
Interview with SciLine
Can you give us some basic information about whooping cough?
[0:00:41]
JOSHUA SHARFSTEIN: Sure, whooping cough is a disease caused by bacteria. It’s transmitted person to person through respiratory droplets, so people cough up the bacteria and other people get it. It can cause a very severe disease in small babies, but it also can cause a very prolonged cough in older adults.
What are the symptoms of whooping cough?
[0:01:09]
JOSHUA SHARFSTEIN: So whooping cough generally starts just like a cold with a little runny nose, and then comes the cough. And the cough can be quite ferocious. If it’s a severe case, people have trouble catching their breath, and so they cough, cough, cough, cough, cough, and then they have a huge effort to bring in air, and that causes the whooping sound like, ooh, like that. And that cough can actually make it hard for people to get enough oxygen, and that’s where you see some severe complications. For patients who make it past that phase, they can have some damage to the lining of their respiratory tract, and that leads to a prolonged cough. The disease used to be called the cough of 100 days because that cough can last for months.
What’s going on with whooping cough in the U.S.?
[0:02:01]
JOSHUA SHARFSTEIN: So whooping cough is on the rise. During the pandemic the levels of cases that were transmitted from person to person really fell because we were wearing masks and washing our hands more frequently. But now that the pandemic is behind us, the disease is roaring back. We had five times more cases in 2024 than 2023, and already we’ve seen, in 2024, about 10 children die.
How contagious is whopping cough?
[0:02:37]
JOSHUA SHARFSTEIN: Very contagious. If one person in a household has whooping cough, there’s about a 50% or more, in some cases, chance that other people will get infected too. So, it is transmitted when people cough up the bacteria and then other people bring it in.
How common are complications from whooping cough?
[0:03:03]
JOSHUA SHARFSTEIN: You know, for most adolescents and adults into middle age, severe complications are not that common. It can cause that very chronic cough, but very severe complications are pretty rare. Where you see more severe problems are in younger children, particularly babies, because they have trouble catching their breath, and they actually can become cyanotic. They can lose access to oxygen, they can develop encephalitis, and it can even be fatal. The other age range is for much older adults—they also can develop pneumonia and other complications from a whooping cough.
What vaccine prevents whooping cough, and who should get it?
[0:03:48]
JOSHUA SHARFSTEIN: There is a vaccine for whooping cough—it’s called the pertussis vaccine—and everybody should get it. It’s given regularly to children at ages 2, 4, 6 months. There’s a fourth shot between 15 and 18 months, and a fifth shot between four and six years old. And then it’s also given to young adolescents at age 11, and it’s also given routinely to pregnant people in their third trimester.
How well do the pertussis vaccines work at preventing whooping cough?
[0:04:09]
JOSHUA SHARFSTEIN: So, they’re very good at preventing that severe disease, and it’s very rare for a baby who has been fully immunized to develop severe symptoms. But it is possible to get a more mild case, and the vaccine potency wanes over time, which is why there’s a need for those booster shots.
How safe are the pertussis vaccines, and how do we know?
[0:04:51]
JOSHUA SHARFSTEIN: So extremely safe. They’ve been around for decades, and there are millions and millions of people who have taken them. There’s a lot of studies on the safety of this vaccine, and what we know is that it can cause some adverse effects, like redness and pain at the injection site. Those are by far the most common effects, and rare serious side effects are extremely rare—like allergic reactions. So overall, the benefits of this vaccine to prevent a severe disease, particularly in babies, far outweigh the very, very small risks.
Why do doctors recommend multiple doses of the pertussis vaccines?
[0:05:34]
JOSHUA SHARFSTEIN: Sure, so the whole idea of a vaccine is it’s training our immune system to recognize a bacteria or virus before we come in contact with it so that bacteria or virus doesn’t make us really sick. Instead, our immune system is ready for it, and it kills the bacteria virus before that kills us. And it’s really a question of how many doses you need to train your immune system. Some vaccines, it’s just one dose, and your immune system is ready to go. For the pertussis vaccine, it needs multiple doses in order to really train your immune system to protect you.
Should parents of children who are too young to be fully vaccinated take special precautions?
[0:06:21]
JOSHUA SHARFSTEIN: Yeah, so the most important thing is that parents should make sure that they’re up to date on their vaccinations for pertussis themselves—that’s really important. And then they should be careful about anyone coughing in the household. If someone starts to cough, particularly, you know, a bad cough should be evaluated, because if that turns out to be pertussis, whooping cough, then the doctor might actually want to treat the baby—give the baby the medicine for whooping cough—in order to protect that baby from getting whooping cough. So, if there’s someone in the household who’s known to have this, there are definitely things that can be done to protect the baby.
Once a person has whooping cough, how do doctors treat them?
[0:07:00]
JOSHUA SHARFSTEIN: The most common treatment is five days of an antibiotic called azithromycin, and it’s very good for killing the bacteria. But if you’ve had the cough for a very long time, you might be at the phase where it’s just the damage that was done to the respiratory tract, and the antibiotics might not help that much. So, you really want to get treated as early as possible.
What’s it like to treat a child with whooping cough?
[0:07:27]
JOSHUA SHARFSTEIN: Well, I probably should have mentioned that I’m also a pediatrician, and I have taken care of kids with severe whooping cough—little babies with severe whooping cough—and I remember them because they were really suffering and really struggling to breathe, and their parents were worried sick about them, and that’s why I got my children vaccinated against pertussis, against whooping cough, and why I certainly recommend that everyone do the same.
