Babies receive their first whooping cough vaccination at two months. Newborns and infants too young to be vaccinated face the greatest risk of serious complications or death from this highly contagious disease. (Photo: Pospiech via Wikipedia)
Babies receive their first whooping cough vaccination at two months. Newborns and infants too young to be vaccinated face the greatest risk of serious complications or death from this highly contagious disease. (Photo: Pospiech via Wikipedia)

Children who miss one or more of their scheduled whooping cough shots face a much greater risk of catching the potentially deadly disease, a new study shows. Risk jumps substantially with each delayed or skipped shot: children denied all recommended shots are 30 times more likely to get sick.

The results, published online Monday in JAMA, reflect a growing tendency among parents to delay or refuse certain childhood vaccinations. More than 10 percent of parents now “under-vaccinate” their kids, citing concerns about vaccine safety. Despite ongoing education campaigns to dispel misguided fears about vaccines, some parents still worry that too many vaccines “overwhelm” a young child’s immune system while others believe that specific vaccines can cause autism in healthy children. Neither is true.

Whooping cough (also known as pertussis) causes violent, spasmodic coughing fits that produce the disease’s trademark “whoop” as victims desperately struggle to breathe. Babies too young to vaccinate are at greatest risk of serious complications, as the infection quickly overwhelms their immature bodies. Last week, two newborns died in Texas during one of the biggest whooping cough epidemics there in 50 years. Pertussis can also cause seizures, brain damage and mental retardation as infection robs tissues of oxygen.

During the 2010 California epidemic—the largest in 60 years—more than 9,000 people contracted pertussis, and ten infants died. Of 159 pertussis deaths reported to the CDC between 2004 and 2011, nearly half were babies under three months old. To protect babies too young to get vaccinated, health officials urge pregnant women to get a booster shot during the third trimester.

Veering from a Science-Based Schedule
The Advisory Committee on Immunization Practices sets the childhood immunization schedule based on evidence-based approaches to reduce vaccine-preventable diseases. The ACIP recommends that children receive five doses of the DTaP shot—a diphtheria, tetanus and aceullar pertussis combination vaccine—between the ages of two months and six years.

Parents worried about vaccine safety have increasingly adopted alternatives to these well-studied schedules, choosing to delay, space out or forgo shots altogether. None of these options has been studied to understand just how they affect disease risk.

Toward that end, epidemiologist Jason Glanz and a team of health experts from across the country evaluated the consequences of delaying or refusing a child’s DTaP vaccination amid ongoing pertussis outbreaks. The team reviewed the medical records of children born between 2004 and 2008 at eight managed care organizations from coast to coast, including Kaiser Permanente Northern and Southern California. They identified confirmed cases of pertussis, then determined whether children were under- or fully vaccinated.

As expected, the more DTaP shots missed, the higher the risk. Missing or delaying three doses made a child 19 times more likely to get pertussis. Under-vaccinating for all four scheduled shots made a child 30 times more likely to get pertussis. More than a third of pertussis cases in kids ages three months to three years old could have been prevented if they’d received their shots on time.

It’s not surprising that deviating from the recommended schedule places children at much greater risk of getting a serious infection, says Glanz, an investigator with the Institute for Health Research at Kaiser Permanente Colorado. “The problem is that there are a lot of parents who think it’s okay to push [the vaccinations] off. They need to know that pushing them off places their children at risk, especially at a time when the disease is particularly serious.”

Theories without Evidence
Glanz and his colleagues didn’t interview parents for this study, so it’s not clear why they chose not to vaccinate their children against a disease that kills mostly babies. In another study, Glanz found that although parents typically trust their pediatricians for most medical advice, they think doctors don’t provide “balanced” information about vaccination risks and benefits. For information on risk, parents rely on other parents, web sites, advocacy groups, celebrities, and books that advocate alternate schedules and raise unfounded fears about vaccine dangers.

Fears about the pertussis vaccine surfaced in the early 80s, after the TV documentary “Vaccine Roulette” blamed the vaccine for leaving children dead or brain-damaged. The original vaccine contained the whole (killed) pathogen and so delivered hundreds of antigens to trigger an immune response. More antigens meant broader protection against numerous strains of the pathogen, but also produced more side effects, including febrile seizures, irritability, and a short-lived though frightening condition (called hypotonic hyporesponsive syndrome) that makes children limp and unresponsive.

Studies found no support for long-term brain damage or other terrible dangers raised by “Vaccine Roulette,” but many parents, understandably scared by what they saw, stopped vaccinating their children. Pertussis has been on the rise ever since, but not simply because parents shun vaccination. Public health officials attribute part of the increase to better recognition of the symptoms, now that the disease is common again, along with waning immunity and the evolution of more aggressive pathogens. To alleviate fears about the whole-cell vaccine, manufacturers created the current acellular version (DTaP) with just three antigens. Though DTaP is extremely effective in infants and young children, as Glanz’s study makes clear, it can’t target all circulating pathogen strains and wears off over time, which is why public health officials recommend booster shots for kids entering seventh grade.

The JAMA study paints a disturbing picture that many parents believe vaccines are more dangerous than an infectious disease that once killed 9,000 people a year. But it also shows that the childhood DTaP vaccine works. “Whatever concerns we have about the vaccine’s effectiveness, this study shows it prevents a lot of cases of serious infection without hurting kids,” says Roger Baxter, co-director of Kaiser Permanente’s Vaccine Study Center in Oakland. Baxter wasn’t involved in the study.

Although the childhood immunization schedule protects against more pathogens than ever before—thanks to discoveries that led to new vaccines—shots today elicit an immune response with just a fraction of the antigens present in older vaccines. That’s what vaccines are all about, says Baxter: protecting children against a disease by inducing an immune response without producing the illness. “It’s just sad that some people are afraid of it.”

Glanz wants parents to know that public health experts are on their side. “We know parents want to do what’s best for their child, and that’s our objective too,” he says. “Public health experts do studies like this not because we’re pro-vaccine but because we’re pro-child. We know these decisions can be difficult and there’s a lot of confusing information out there. We want to help parents make the best decisions for their child.”

The Real Vaccine Roulette: Missing Your Baby’s Scheduled Shots 10 September,2013Liza Gross

  • dr.I

    It has been my experience as a parent, clinician and ex-scientist that the fewer vaccinations a child has, the healthier they are. Those with no shots are the healthiest. Of course it also has to do with the parents caring, education, and diet. The louder the hype gets, the more one should be skeptical.

    • yngvai

      Dr. I,

      Your clinical experience is no replacement for peer reviewed research. I’m also having my doubts about your status as an ex-scientist; if you are, it certainly is not in the field of immunology. There is absolutely no scientific evidence to support your assertion that “the less vaccinations a child has, the healthier they are.” The unvaccinated children in the recent Texas church who came down with measles would certainly not fit into the “healthiest.”

      Vaccination is not about hype. It is about science…science by the best immunologists and epidemiologists in the world. It is nothing short of dangerous to encourage non-vaccination.

      • dr.I

        If all the immunologists believe the same thing, that is not science, that is dogma, and their message is propaganda, influenced by a political and economic agenda. Real science allows disagreement; medical practice does not qualify as science, because the practitioner’s are ostracized if they don’t stick to the party line. I suggest, for example that you read Dr. Wakefield’s early papers with an open mind. He is a real scientist.

        • yngvai

          Dr. I.,

          First, you have discredited yourself by mentioning Dr. Wakefield, who falsified his data regarding vaccines and autism. Why you would even support such an individual is quite baffling.

          Second, immunologists don’t just “believe” the same thing. They all agree because that is how strong the evidence is, no different from how scientists agree that the earth is round because that is how strong the evidence is. Their message is not propaganda. And exactly what economic agenda to immunologists have?

          Third, you provided no scientific evidence to support your assertion that “the less vaccinations a child has, the healthier they are.” Thus, I will consider that statement nothing more than an unsupported assertion, which all the scientific evidence indicates is not true.

          Yes, real science allows disagreement, if the evidence is not clear. Clearly you are not a scientist as you claim, because if you were, you would see that the peer reviewed literature is full of disagreement about many different areas of science. But when it comes to the safety and efficacy of vaccination to prevent deadly diseases, there is no disagreement because the science is overwhelming and solid.

          • dr.I

            I’d say the “science” concerning vaccinations is underwhelming and more liquid than solid. If you believe that Dr. Wakefield falsified his data, you obviously only know the story 2nd or 3rd hand.
            It is true that there can in science, be total agreement sometimes, like when facts are established, as for example, nobody disputes that DNA is the genetic material. But I’m talking about the growing point of a new field, where the “consensus” is more manufactured than real. One example of poor vaccine science is how flu shots are tested. All they do is inject the dead virus into healthy people and look for an antibody response. If 60 or 70% of people have a response, then the vaccine is deemed “effective.” In no way does this prove that the actual flu will be prevented, especially in a person with a weak immune system. You call that “solid and overwhelming?”

          • Sullivan ThePoop

            That is only to test seroconversion. They also challenge the study participants with influenza. Nice try though.

          • yngvai

            Once again, Dr. I, you demonstrate that you know very little about vaccines or vaccine science.
            First, the evidence was overwhelming that Wakefield had not only falsified his data, but had engaged in other forms of misconduct as well. If you have information to refute that evidence, then please provide it. I’m sure the British General Medical Council, and the editorial board at the Lancet, would like to hear that evidence since obviously the evidence against Wakefield was so strong that they both retracted his 1998 publication and removed him from the Medical Register.
            You even demonstrate a lack of knowledge as to how flu shots are tested. Measurement of antibody titres is only to test seroconversion, as another commenter here has stated. There is much more that goes into flu vaccine efficacy research, including clinical trials where individuals are directly challenged with influenza virus, as well as extensive epidemiological work.

            I’m also still awaiting your evidence that children who do not receive vaccines are healthier than ones who do. If you are a former scientist as you claim, I would think you would understand that anecdotes are not scientific evidence.

          • yngvai

            I also heard about the Nazi Holocaust 2nd or 3rd hand. By your logic, would that mean it never happened or that I shouldn’t trust the overwhelming evidence that it did happen?

        • Sullivan ThePoop

          Dr. Wakefield was a real scientist until he decided to take money to produce an unethical and inaccurate study.

        • Sullivan ThePoop

          We believe the science which is consistently on the side of vaccination and has been for over 100 years.

    • Sullivan ThePoop

      Well, since the hype is all on the antivax side I completely agree.

  • dr.I

    1)If you lived in Iran, where the official attitude a few years ago was that the holocaust never happened, would you be one of those government apologists who towed the line?
    Like so many medical doctors in the U.S. who do what they’re told by the CDC?
    2) The point is that medical science has been so corrupted by those with either deep pockets or an ideological agenda that even so-called peer-reviewed studies can’t always be trusted, especially when it comes to the treatment of disease. My motto for years has been: “one good, solid anecdote is worth five questionable double-blind studies.”
    3) You keep asking about evidence that unvaccinated children are healthier. I told you it was observational. Including my own two children, now in their thirties, my grandchildren, and many dozens of other children that I’ve observed over the years. Its really common sense. If you look at all the toxins in those vaccine formulations, from Hg and Al to formaldehyde, MSG, antibiotics, and who knows what inadvertent contaminants, its a wonder more children don’t succumb to that onslaught.
    4) Now you tell me what the actual evidence was that Dr. Wakefield falsified his data. Maybe I can be convinced?

    • dandover

      My motto for years has been: “one good, solid anecdote is worth five questionable double-blind studies.”

      Translation: “Hello. I am a moron.”

    • Benjamin Ashraf

      Dr. I,
      As a doctorate student in public health I was a little saddened to read your comments especially considering your background. Especially about the peer reviewed studies not always being able to be trusted. Now I am glad your children turned out healthy but if you look at the historical evidence on vaccinations going back to polio and smallpox you are able to see how effective vaccination campaigns have been. As well the additives in vaccinations have never been associated with an increase in adverse reactions in any study that I have read, and if you do have one please post it here so others can see. While you are entitled to whatever you wish to believe the fact is that we are seeing the legacy of those who choose to not vaccinate with the recent outbreak in Texas for measles as well as the cases seen in Seattle and Boston, as well as the outbreak of mumps that occurred in New Jersey. Now I am naive to say we should not question aspects of science but there needs to be evidence to support your claim beyond a single anecdote as you suggest. And as far as massive corruption, I find it hard to believe that so many researchers would conspire on one issue merely for money when vaccines are one of the worst money making agents for pharmaceutical companies. I hope as a scientist that you would consider the ramification of your claims next time because they can do only more harm then good.

  • Anupriya

    Keeping track of vaccinations for your baby is very important as it protects your child against a range of serious and potentially fatal diseases. With busy schedules and multiple tasks at hand, it becomes extremely difficult to monitor immunizations & their dates.

    To overcome this problem, I came across a simple vaccination app, VacciTrack, that helps to keep track of your child’s immunization schedule till the age of 10. It gives you reminder before the day of vaccination and a full chart along with missed & upcoming vaccines. Moreover, you can also make changes to the schedule as per your doctor’s recommendations.

    Have a look –


Liza Gross

Liza Gross, an award-winning independent journalist and senior editor at the biomedical journal PLOS Biology, writes mostly about conservation and public and environmental health. She was a 2013 recipient of the NYU Reporting Award, a 2013 Dennis Hunt Health Journalism fellow and a 2015 USC Data Journalism fellow.

Read her previous contributions to QUEST, a project dedicated to exploring the Science of Sustainability.

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