Persistent Pertussis

“You think the safest place in the world for your baby is wrapped in your arms. But it can also be one of the most dangerous.”

These are the opening lines of a widely syndicated pertussis commercial encouraging people to get vaccinated. It paints a scary picture of what the severe cough looks and sounds like in infants but even scarier is the fact that the incidence of whooping cough is on the rise despite the availability of vaccines.

Vaccine Effectiveness

Prior to the 1940s, more than 200,000 cases of pertussis were reported each year according to the Centers for Disease Control and Prevention (CDC). After the first whole-cell DTP vaccine was introduced and was determined to be 70% to 90% effective after four doses, the incidence was reduced to less than 10,000 by 1965.1

“Essentially what they did is they took the bacteria and killed it and mashed it up and gave it as a shot and that helped to induce an immune response in the patient,” explained Daniel McGee, MD, a Spectrum Health Medical Group physician who practices as a pediatric hospitalist at Helen DeVos Children’s Hospital in Grand Rapids, Mich. “There were some side effects associated with it – there were fevers, swelling, and some redness at the injection site.”

These side effects could not be ignored and the vaccine was reformulated in 1996 to create an accelluar pertussis vaccine, DTap which only uses parts of the cell. Making the switch minimized side effects but many believe it also lessened the protection time for babies and young children who are supposed to get a dose at 2, 4 and 6 months, and again between 15 and 18 months with their last shot around the time they start kindergarten between the ages of 4 and 6. Because of waning immunity, the vaccine offers solid protection for just two years and gradually decreases. Approximately 3 in 10 kids are only partially protected five years after their last dose.

SEE ALSO: Anti-Vaccine Movement

In 2014 pertussis was declared an epidemic by the California Department of Public Health. Recent estimates suggest the US now exceeds 30,000 cases of pertussis each year but those are only the cases that get reported.2 A study presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy in 2015 found that the true incidence of pertussis in Americans under the age of 50 could actually be anywhere from 58 to 96 times as many cases.3

“Right now the recommendation is to get a booster dose for an adolescent or a child. If you had your initial series of them as a child, then you should get another one about 11 years of age,” said McGee. “At this time there’s no recommendation for any third booster but there may be a recommendation somewhere down the road for more boosters.”

Anti-Vaccine Movement

Newborns can’t receive the full set of immunizations until they’re older, which is why the March of Dimes and similar organizations advocate for others to get vaccinated through TV commercials and social media.

“Pertussis is a risk for anybody who is not vaccinated,” noted Alison Matthews, MD, a pediatrician based out of Cleveland, Ohio. “Babies under one year old are at greatest risk for severe illness.”

One way they can receive protection is through their mother while still in-utero. The CDC recommends all pregnant women get the Tdap, the pertussis vaccine for adults, during their third trimester.

“Babies obviously are much more fragile than adults,” stressed McGee. “They don’t have as much pulmonary reserve so when they do get these coughing episodes it can tip them over the edge.”

It’s comforting to know that the majority of the population does receive their full vaccinations. However, there are also a growing number of parents who are against immunizations, meaning they opt their children out of vaccines for religious reasons or as a result of common misconceptions like the belief that vaccines can cause autism.

“We saw an outbreak here in Michigan two years ago that started in a school where a large percentage of the children weren’t vaccinated and so the vaccine objectors are not helping things at all,” noted McGee. “They don’t realize not only are they protecting their own child in getting vaccines, they’re helping to protect the rest of the community as well.”


It’s also important to get vaccinated because pertussis was never completely eradicated from the United States even when vaccinations were strongest. Worldwide, an estimated 16 million cases of pertussis and 195,000 pertussis-related deaths occur each year.4

“Symptoms include runny nose and cough. Young children may develop apnea,” said Matthews explaining what pertussis or whooping cough can look like for different people or age groups. “As the disease progresses, the cough worsens and people may cough to the point of vomiting.”

When people travel out of the U.S. they are subjecting themselves to larger outbreaks specifically in underdeveloped countries where vaccinations are either unavailable or rates are extremely low.

Back in 2011, approximately 90% of all measles cases reported in the U.S. came from other countries. Meanwhile today’s Zika virus has yielded 193 travel-associated cases as of March 9.4


To prevent an outbreak in the U.S., providers continue to stress the importance of vaccines as the best line of defense against pertussis and other viruses. If caring for a baby it’s important to make sure everyone the baby comes in contact with is also up-to-date on all of their vaccinations.

Before a trip or vacation overseas it’s a good idea to find out if any health advisories are in effect for the travel destination by visiting the Bureau of Consular Affairs website through the U.S. Dept. of State ( Lastly, it’s important to stay informed on vaccine recommendations and other medical information that can help keep families healthy.

1. Centers for Disease Control and Prevention. Pertussis 2015
2. American Academy of Family Physicians. Pertussis Is Latest Disease Outbreak Concern in United States 2014
3. Chest Physician. Reported pertussis underestimates true incidence by up to 93-fold 2015
4. Centers for Disease Control and Prevention. Zika Virus Disease in the United States, 2015-2016

Chelsea Lacey-Mabe is a former staff writer.

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