Pertussis: Waning Vaccine Immunity Leads to Resurgence


Julia A. Piwoz, MD, FAAP
Hackensack Meridian Health/Hackensack University Medical Center, Hackensack, NJ

Pertussis, or “whooping cough,” can cause apnea, seizures, anoxia, and even death in infants. In young school-aged kids, it can cause pneumonia, vomiting from the violent coughing fits, and worsened colds or respiratory infections soon after. Patients can cough for up to 3 months after having pertussis. Adults with pertussis can break ribs from coughing so hard. They can develop hernias and have incontinence. So, the best way to prevent pertussis is through vaccination. 

Pertussis is endemic in the United States. We tend to see peaks in the cycle every 3 to 5 years, and there is a very interesting reason behind that. We are, in some ways, victims to our own success when it comes to pertussis. 

Origins of the Vaccine
Over the years, we have gotten better about identifying and testing for pertussis. The first pertussis vaccines created were whole-cell vaccines. And once school-aged children were immunized with the whole-cell vaccine, cases of infection were reduced dramatically. But that vaccine had side effects that were thought to be due to the pertussis part of it, so new vaccines were made that did not include the entire organism. This was called the acellular pertussis vaccine, and it is what we use today. 

Although the acellular vaccine proved to be safe and effective, the protection does not last as long as the older vaccine. Now, instead of seeing infants and school-aged children getting sick with pertussis, we see more teenagers and adults becoming sick because the vaccine immunity has worn off and their immunity has not had time to be boosted. 

When teens and adults get pertussis, they do not have the “whoop” of whooping cough, and they may have symptoms that can be confused with a lot of other illnesses, like colds and asthma, and that can lead to a delay in the diagnosis and delay in treatment. People with pertussis cough a lot, and if left untreated can be contagious for 3 weeks after the cough starts. A single person with pertussis can typically infect 12 to 15 other people during that time. 

Vaccinate to Prevent the Spread
One important thing to know about the vaccine is that receiving it, and even getting pertussis, may not prevent individuals from actually getting infected. Individuals may still encounter the bacteria, and it may still get into their body, especially if someone in their household has it. But the vaccine can prevent individuals from getting sick. 

If someone is not sick with pertussis, then they will not have violent coughing fits and, therefore, may not spread the disease to others as readily. This is really important to tell your patients, because some of them may have infants at home or are around people with high-risk conditions. People tend to forget that grandparents and babysitters can also spread the disease, so the vaccine is recommended. Health care workers are at high risk of being exposed and spreading it, so the vaccine is recommended for us as well.

Vaccination During Pregnancy
Current recommendations advise a woman to receive the TDAP, or pertussis, vaccine with each pregnancy. And there is actually some really good reasoning behind this. Moms will have the closest relationships to their babies, both before and after the baby is born. So, let’s face it, if a mother gets pertussis, the baby will too. And one of the scariest symptoms of pertussis in babies is apnea. So, it is important to prevent the disease in the mother in order to prevent the disease in the baby. But it does not stop there. 

Moms actually pass antibodies to the baby during pregnancy that protect the baby, which cross the placenta in the third trimester. If a woman is immunized earlier during her pregnancy, not only is her own immunity boosted, and she will be less likely to get sick, but she also passes that immunity in high levels to the baby. Both mom and baby end up being protected by mom getting the vaccine. 

The question always comes up about why we advise this for every pregnancy. Well, a mother’s antibodies, like everyone else’s, start to wane over time—even in a short a period of time as a year or two. So, less antibody is available to cross the placenta and protect the next pregnancy. We want to give every child in the family the same advantage against the deadly disease. 

Julia A. Piwoz, MD, FAAP, is the Chief of the Section of Pediatric Infectious Diseases at the Joseph M. Sanzari Children's Hospital at Hackensack Meridian Health Hackensack University Medical Center in New Jersey.