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Home » Undervaccinating against pertussis puts children and community at risk

Undervaccinating against pertussis puts children and community at risk

whooping_cough-babyOver the past year or so, there have been several outbreaks of whooping cough (Bordetella pertussis), including one that reached epidemic levels in Washington state, which has been considered one of the worst pertussis outbreaks in the USA during the past several decades. The disease lead to 18 infant deaths in the USA during 2012.

The original DTP vaccine (diphtheriatetanus and pertussis) became available in the USA in 1948 and was critical to dropping the number of cases of whooping cough from 260,000  in 1934 to less than a few thousand per year in the 1990′s. The original vaccine contained what was called “whole-cell” pertussis, which includes all of the antigens of the pertussis bacterium, partially because it wasn’t understood (and to some extent still not fully understood) which antigens on the bacteria actually induce the proper immune response to have the body destroy a pertussis infection. In the late 1990’s, the Advisory Committee on Immunization Practices (ACIP) recommended that the USA switch to the acellular form of the vaccine, known as DTaP (a pediatric vaccine to immunize against diphtheria, tetanus and pertussis) or Tdap (the older children/adult version of same vaccine).

ACIP recommends that children should get 5 doses of DTaP, one dose at each of the following ages: 2, 4, 6, and 15-18 months and 4-6 years. Those children who are not completely vaccinated according to these ACIP recommendations for pertussis are considered to be “undervaccinated.” 

Whooping cough is a serious disease that has significant complications for children:

  • 1 in 4 (23%) get pneumonia (lung infection)
  • 1 or 2 in 100 (1.6%) will have convulsions (violent, uncontrolled shaking)
  • Two thirds (67%) will have apnea (slowed or stopped breathing)
  • 1 in 300 (0.4%) will have encephalopathy (disease of the brain)
  • 1 or 2 in 100 (1.6%) will die

Even in adults, there are substantial complications, such as broken ribs from coughing, that can have a significant impact on the overall health of the individual.

Despite the medical understanding of the consequences of whooping cough, a study published in March 2013 showed that the rate of undervaccination increased significantly in several US managed care organizations dropped significantly between 2004 and 2008. The reasons for undervaccination included parental choice (vaccine refusal) and other typical reasons, including lack of health care and medical contraindications to vaccination. 

Several studies have shown a reduced protective effect of the pertussis vaccine (probably as a result of the acellular version of the vaccine) which may have lead to the resurgence of pertussis in the USA. These issues have lead to a few myths that include the belief that children who are vaccinated with DTaP are actually at higher risk of contracting pertussis (fully refuted). The vaccine quack website, Age of Autism, pushed other myths about DTaP vaccination. These various ignorant beliefs about the pertussis vaccine has strongly contributed to the reduction in the uptake of the pertussis vaccine amongst the most vulnerable children.

A recently published study examined the risk of pertussis infection in undervaccinated children, between the ages of 3 and 36 months. The researchers examined medical records of over 300,000 children enrolled in 8 midwest US managed cared organizations, which usually have detailed and centralized health care records of patients. They identified 72 children with pertussis (confirmed by a laboratory analysis, where the reviewer was blinded to vaccine status). This infected group was compared to 144 non-infected children randomly chosen to match the demographics of the 72 infected with pertussis. The results were dramatic:

  • An unvaccinated child was 2.25X more likely to contract pertussis than a child with just one vaccinations.
  • They were 3.41X likely to get pertussis than a child with two vaccinations.
  • They were 18.56X more likely to contract the disease than a child with three vaccinations.
  • And, most dramatically, they were 28.38X more like to get pertussis than a child who is full vaccinated.
  • In fact, the overall risk of a non-vaccinated child contracting pertussis is 4.36X than children who have had any number (1-4) of DTaP vaccinations.

This remarkable and statistically significant reduction in risk of contracting pertussis, especially after being fully vaccinated at 36 months (4 immunizations) fully refutes and debunks the belief, pushed by vaccine deniers, that somehow vaccinated children are the ones catching and passing along the disease.

In fact, the authors clearly conclude that:

Our data suggest that undervaccination, whether due to parental refusal of vaccines or other barriers to health care, is an important contributing factor, especially given the documented increasing rates of undervaccination in 2 recently published studies. Undervaccination with DTaP vaccine places infants and young children at increased risk for pertussis. Although not supported by our data, it is also possible that undervaccination indirectly threatens the health of surrounding populations that are at high risk for serious complications from pertussis, such as infants who are too young to be vaccinated.

We believe that our study supports on-time vaccination with DTaP vaccine, as recommended by the Advisory Committee on Immunization Practices.

It’s useless to engage intelligently with the ignorant vaccine refusers that populate the backwoods of the internet. But if you’re undecided about vaccines, or you keep hearing the lies of the antivaccination gang, listen to real science. Pertussis can kill, it can harm, and it can put your precious child into an intensive care unit in a hospital. This will cause you sleepless nights, unbelievable stress, and untold economic damage. Your child will be in pain. Your child’s pain will break your heart.

But we have scientific evidence, at the highest possible level of reliability, that shows vaccinating your child with all age-appropriate vaccines will make their life better, and as a consequence, make your own life better.

You can listen to the lies of those who suffer from the Dunning-Kruger effect, individuals without any education or any real scientific knowledge but who have an illusory belief in their own superior knowledge, and risk your child’s health. Or you can listen to hard-working, well educated, and very devoted individuals, who make their life’s goal to saving children’s lives and who produce evidence strongly in support of the effectiveness of pertussis vaccines. Yes, there’s a choice, but the evidence, the highest possible quality evidence, sits on the side of the safety and effectiveness of vaccines. 


If you need to search for accurate information and evidence about vaccines try the Science-based Vaccine Search Engine.


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Michael Simpson

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