Pertussis and Parents Who Don’t Vaccinate: One Physician's Experience

I received a call from an administrative assistant from one of the high-end private schools on the west side of Los Angeles requesting the medical records of one of my patients. Since there was no parental consent, I politely declined and hung up the phone. It seemed like a flicker on my radar screen that would just fade into the usual background noise of running a practice . . .

Then more calls and patients arrived. Everyone was worried about pertussis, the causative agent of whooping cough. Practicing in Beverly Hills and serving the western part of Los Angeles, I have diagnosed whooping cough at least once per month for the last 5 years. I take a western, no nonsense approach to vaccines: Please vaccinate your children. It’s ok to avoid the vaccines with multiple disease strains – break them up, get them separately. It’s fine to ask for the ones without mercury. Please - just do it. 

Bordetella pertussis is the causative agent of whooping cough. Before vaccines were available in the 1940s pertussis was a major cause of morbidity and mortality in children. According to CDC records, there were 200 000 cases annually. After mass vaccination, the case number decreased substantially until the 1980s when the caseload began to increase. There were 48 277 cases reported in 2012. This was the peak, and since then the prevalence has waxed and waned.

Bordetella pertussis produces adenylate cyclase, agglutinogens, filamentous hemagglutinin, pertactin, pertussis toxin, and tracheal cytotoxin. These all contribute to the disease process. Once infected, a patient can have a debilitating cough for 6 months followed by the development of bronchiectasis. This sets the patient up for repeat chronic infections with bacteria that are often resistant to multiple antibiotics. Azithromycin and medication for symptomatic relief are the treatments of choice. I often give the antibiotic, a short-acting bronchodilator, an inhaled corticosteroid, and benzonatate.

An average case presentation. A healthy teenager with a ferocious cough comes in for an urgent, after hours, appointment. The cough has persisted for >2 weeks. He has often completed a Zpak and had a visit to the pediatrician. The cough leads to vomiting and sometimes a little hemoptysis. When that happens, the alarms go off and the family mobilizes, shifting to hyperdrive to get things in order.

Background. The patient’s home usually consists of college educated parents who work hard in their home and work lives. They seem sensible and even in touch with their spiritual side. But after hearing some horror stories about vaccines-they search the Internet. And they decide that the risk of vaccine side effects is too great.

Emotion shapes decisions. The parents are well informed. The Internet gives them access to the same information that their doctors have. So why do they make the wrong decision? Emotion destroys the self-control that is essential in rational decision making. For example, reading a bone chilling description of a single bad reaction to a vaccine creates a nightmare scenario that can seem real. The vivid details of a single event will replay more frequently than the memory of cold statistics. This suggests that probability judgements are often attached not to events, but to descriptions of events.

Sample size shapes decisions. In trying to make sense of our world, we often base decisions on small samples that lead us to erroneous choices. It is admittedly difficult to find straight answers on serious side effects of pertussis vaccine. A search of the CDC’s Vaccine Adverse Event Reporting System showed that since June of 1990, there have been 139 reports of a serious adverse event related to Pertussis, Adsorbed Vaccine. The problem, at least for a parent looking for credible data, is that the denominator is missing. That is, what is the number of pertussis vaccines that have been given in those last 29 years?

Let's look at the math. According to the last census, in 2017 there were 127 650 000 people between ages 0 and 29 years in the US. Vaccine schedules recommend 5 pertussis vaccines in a lifetime. So, if everyone aged ≤29 years were fully vaccinated, 638 250 000 vaccines would have been given. Which translates to a 139/638 250 000 = 0.00000016% chance of an adverse event. That is a very small risk. Much less than actually getting the disease.

The patient always gets at least 1 Zpak (sometimes 2) and usually some benzonatate and inhalers. Reassurance and patience are always the best tactics. I always spend the extra time answering questions about the dangers of antibiotics and steroids. The crux of every sound medical decision centers on a risk vs benefit analysis: Is the risk of treatment less than the risk of no treatment? Treatment becomes more attractive as the consequences of disease get worse. This applies to treating a teenager for pertussis and vaccination in the first place. And the conversation always returns to vaccination. The error the parents made when they decided not to vaccinate?