Protecting Babies By Getting Your Tdap Booster? Ponder This.


A scary word for parents and grandparents across the country.

I’ve had friends and even close family members seek out and receive an aP (pertussis/whooping cough) vaccine in the hopes of protecting the babies in their life.

One question arises, “Why does the general public believe that getting this vaccine will prevent transmission of the B. Pertussis toxin?”.

I think there exists a great misconception of information regarding the disease and vaccine regarding the effectiveness on transmission of pertussis (whether it be intentional or not).

Let’s start at the beginning – according to the manufacturer.

It is unknown whether immunizing adolescents and adults against pertussis will reduce the risk of transmission to infants[1]

There are currently no data which demonstrate a reduction of transmission of pertussis after immunization with BOOSTRIX.[2]

…booster immunization of adults with acellular pertussis vaccines was not found to increase bactericidal activity over preimmunization levels.[4]

Why not be extra-safe and get the vaccine anyways? 

Vaccinated adolescents and adults may serve as reservoirs for silent infection and become potential transmitters to unprotected infants (3-11)….even young, recently vaccinated children may serve as reservoirs and potential transmitters of infection."[5]

(According to the phenomenon coined as “original antigenic sin”) DTaP vaccinated kids might be more contagious when they catch pertussis compared to unvaxed kids after they catch pertussis.[6]

Here, we ask how aP vaccination affects competitive interactions between Bordetella species within co-infected rodent hosts and thus the aP-driven strength and direction of in-host selection. We show that aP vaccination helped clear B. pertussis but resulted in an approximately 40-fold increase in B. parapertussis lung colony-forming units (CFUs).[7]

Further, we show that aP vaccination impedes host immunity against B. parapertussis—measured as reduced lung inflammatory and neutrophil responses. Thus, we conclude that aP vaccination interferes with the optimal clearance of B. parapertussis and enhances the performance of this pathogen. Our data raise the possibility that widespread aP vaccination can create hosts more susceptible to B. parapertussis infection.[7] 

The benefit of the vaccine must be there, we must get it to promote herd immunity…

The efficacy of Tdap vaccination in controlling school or institutional outbreaks has not been evaluated[8][9]

Hold on a second. By giving the vaccine to children (at 2 mo, 4mo, 6mo, 15mo, 4-6yrs, adulthood, and 65 +), the incidence of pertussis has definitely declined... right? 

The overall incidence of pertussis has been increasing steadily since 2007 and has now surpassed peak rates observed during 2004-2005.[10]

Despite high vaccination rates, the number of reported cases of pertussis in the United States has increased steadily since the 1980s.[3]

Chart from the CDC-see reference 10

All Pertussis (aP) vaccines tend to modify duration and severity of disease rather than completely preventing illness.[12]

Pertussis is considered an endemic disease, characterized by an epidemic every 2–5 years. This rate of exacerbations has not changed, even after the introduction of mass vaccination – a fact that indicates the efficacy of the vaccine in preventing the disease but not the transmission of the causative agent (B. pertussis) within the population [13]

I don’t understand. Why isn’t this vaccine effective against the transmission of the pertussis?

Yes, that is the question!

And it looks like the science community is aware of this fault and is attempting to resolve it. Although, all while still fronting that the vaccine is effective at reducing transmission. 

Despite detailed molecular analysis of several virulence-associated factors of B. pertussis, significant gaps remain in our understanding of the pathogenesis of this infection and disease. For instance, we know next to nothing about the cause of pertussis cough or its specific characteristics, and we do not know which bacterial factors contribute to the cough pathology. One of the challenges in understanding this pathology is that there are no small animal models that reproduce the specific characteristics of B. pertussis infection and disease in humans.[14]

Serologic studies of patients in the clinical efficacy trials of the acellular pertussis vaccines did not yield a correlation between antibody levels and protection against pertussis….. The mechanisms of vaccine-induced immunity remain elusive and determination of whether these products are working as initially predicted will require further study.[15]

The research continues to grow regarding the shifting epidemiology and evolutionary changes in Bordatella agent. To understand the current research, let’s do a quick de-briefing.

The current vaccines contain antigenic components for 3 pertussis antigens (proteins found in the bacteria); Filamentous hemagglutinin which protects against filamentous hemagglutinin adhesion, a virulence factor that allows bacterial colonization of the respiratory tract; Pertactin, another virulence factor that functions as an auto-transporter for B. pertussis adherence to lung epithelium and pertussis toxin; and the pertussis toxin itself (PT).

Unfortunately, the vaccine is omitting a vital toxin. The adenylate cyclase toxin (CyaA or also known as ACT).

Two of the most important virulence factors of B. pertussis are the secreted toxins pertussis toxin (PT) and adenylate cyclase toxin (ACT). The emerging picture revealed by the recent literature is that these toxins play a major role in suppression and modulation of host immune and inflammatory responses.[14]

Adenylate cyclase toxin has not been included as a component of newer generation acellular pertussis vaccines, despite the observations that ACT is an important virulence factor for B. pertussis[14]

Current research from a study in 2010 is continuing to add to the base knowledge we have. Some believe that administering a detoxified ACT vector along with the DTaP vaccine, the yielded results will add to the ability to halt transmission. 

detoxified ACT is being developed as a possible vaccine vector molecule, so immune responses to the vector itself would be important. Two recent reports addressed the issue of the use of detoxified ACT as a pertussis vaccine component. In one, co-administration of detoxified ACT with acellular pertussis vaccine to mice significantly enhanced protection against B. pertussis, with adjuvant effects on both Th1 and Th2 immune responses [134]. [14]

Unfortunately, there is unwanted side effects with this (of course) …

In the other, however, detoxified ACT was found to block CR3 transiently and inhibit complement-dependent phagocytosis by human neutrophil-like cells [135], a potentially unwanted side effect[14].

Hmm, so now what?

Whether this investigation will progress further to human clinical trials will probably depend upon a major push towards development of newer acellular pertussis vaccines [14]

On February 22, 2011, the U.S. Supreme Court ruled (in Bruesewitz v. Wyeth) that vaccine makers are immune from lawsuits charging that the design of a vaccine is defective.[16]

Pause for Disclosure

I want to say upfront, that I understand that more would be gained by finding a well-written, objective review article about B. pertussis-specific immunology instead of trying to understand the complexities with a disjointed article presentation.

I am all for an expert on the subject to do the work for me, but unfortunately, I was unable to find one.


What I take away from what I have read over the last few weeks regarding transmission and the DTaP vaccine is that there is still much to learn and it doesn’t seem like anyone knows exactly what is going on (which the scientific community admits to!) with the pertussis bacteria and how it relates to immune response, repeat immune response, and transmission.

What is the most disturbing is that mothers, fathers, grandparents, and children are wholeheartedly depending on this vaccine without any reservation.

The pertussis vaccines do not prevent transmission.

They do, however, prevent or suppress the symptoms (making the individual asymptomatic), and leads to subclinical infection.

I clearly have my reservations and I am skeptical of the promises TV commercials and well advertised web pages claim, especially after taking the time to learn about it myself. I hope this information opens up an internal dialogue in your mind – questioning, learning, assessing.


[1] Adacel Patient Brochure (Sanofi Pasteur) page 5

[2] Boostrix  Production Information (GlaxoSmithKline Biologicals SA) page 3

[3] Weiss, A., Patton, A., Millen, S., Chang, S.j., Ward, J., Bernstein, D. Acellular pertussis vaccines and complement killing of bordetella pertussis. American Society for Microbiology (Infection and Immunity). Vol 72(12): 7346-7351. Dec 2004.

[4] Weingart, C., Keitel, W., Edwards, K., Weiss, A. Characterization of bactericidal immune responses following vaccination with acellular pertussis vaccines in adults. American Society for Microbiology (Infection and Immunity). Vol80(5). May 2012

[5] I. Srugo, D. Benilevi, R. Madeb, S. Shapiro, T. Shohat, E. Somekh, Y. Rimmar, V. Gershtein, R. Gershtein, E. Marva, and N. Lahat. Pertussis Infection in Fully Vaccinated Children in Day-Care Centers, Israel. Emerging Infectious Diseases. Vol 6(5): 526-529. Sept/Oct 2000

[6] James D. Cherry, Dorothy X. L. Xing, Penny Newland, Kashmira Patel, Ulrich Heininger, and Michael J. Corbel. Determination of Serum Antibody to Bordetella pertussis Adenylate Cyclase Toxin in Vaccinated and Unvaccinated Children and in Children and Adults with Pertussis. Clinical Infectious Diseases. Vol 38 (4): 502-507. 2004

[7] Gráinne H. Long, Alexia T. Karanikas, Eric T. Harvill, Andrew F. Read and Peter J. Hudson. Acellular pertussis vaccination facilitates Bordetella parapertussis infection in a rodent model of bordetellosis. Proceedings of the Royal Society (Biological Sciences). Vol 277 (1690):2017-2025. Jul 2010

[8] CDC. Preventing tetanus, diphtheria, and pertussis among adolescents: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccines: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 2006

[9] CDC. Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine. Recommendations of the Advisory Committee on Immunization Practices (ACIP) and recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for use of Tdap among health-care personnel. MMWR 2006;55(No. RR-17):1–37.

[10] CDC-Surveillance & Reporting Trends. Pertussis (Whooping Cough). Last Updated Sept 2011

[11] Wendelboe, Aaron M. MSPH; Van Rie, Annelies MD, PhD; Salmaso, Stefania PhD; Englund, Janet A. MD. Duration of Immunity Against Pertussis After Natural Infection or Vaccination. The Pediatric Infectious Disease Journal. Vol 24(5):S58-S61. May 2005

[12] The Science and Fiction of Pertussis Vaccines. Pediatrics. Vol 104;No 6. Dec 1999

[13] Ori Hochwald, Ellen Bamberger and Issaac Srugo. The Return of Pertussis: Who is Responsible? What Can Be Done? Israel

[14]Vaccine Research Initiative. Vol 8: 301-307. May 2006[14]Nicholas Carbonetti. Pertussis toxin and adenylate cyclase toxin: key virulence factors of Bordetella pertussis and cell biology tools. Future Microbiol. Vol 5: 455-469. Mar 2010

[15] Hewlett, Erik. Pertussis: current concepts of pathogenesis and prevention. Pediatric Infectious Disease Journal. Vol 16(4): S78-S84. Apr 1997

[16] Aaron Kesselheim. Safety, Supply, and Suits — Litigation and the Vaccine Industry. The New England Journal of Medicine. Vol 364: 1485-1487. Apr 2011


  1. Love your blog! I just wish pro vaxers didnt have their ears stapled shut!

    1. Thank you so much Jessica ;)


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