Whooping Cough – Lies, Damn Lies and Statistics

July 26, 2012 by
Filed under: CDC Watch, Vaccine Exemptions, Vaccine/Disease Analysis 

According to the CDC (2002)

However, since the early 1980s, reported pertussis incidence has increased cyclically with peaks occurring every 3–4 years.

And yet  whooping cough increases are being described as though they are a new problem. Here is an example, one of many:

Whooping cough cases have outright ballooned in Washington; state health authorities actually declared epidemic status earlier this year, there has been a 13-fold increase in diagnoses since 2011.

Washington — though home to a lot of highly-educated, tech savvy people — is also the epicenter of the U.S. anti-vaccination movement. Over the last few decades, more and more parents there have opted out of inoculating their kids against preventable illnesses. As some 90 percent of any population must be inoculated for vaccines to work — AKA “herd immunity” — many are blaming Washington’s anti-vax camp for spurring the disease’s spread.

The CDC (from the same document), continues:

The increase in reported pertussis first noted in the 1980s continued throughout the 1990s  Compared with surveillance data for 1994–1996, the pertussis incidence rate among adolescents and adults has increased, 62% and 60%, respectively. The rate increased 11% among infants. In comparison, the incidence rate decreased 8% among children aged 1–4 years and remained stable among children aged 5–9 years. These increases could reflect a change in reporting or a true increase in incidence.

Although underreporting of mild or atypical disease is common, increased recognition and diagnosis of pertussis among older age groups probably contributed to the large increase of reported cases among adolescents and adults. Conversely, an increase in pertussis among infants too young to receive 3 doses of pertussis-containing vaccine suggests a true increase in pertussis circulation. Infants have been a well-recognized high-risk group; changes in diagnosis or reporting patterns in this age group are unlikely. Despite recent changes in pertussis diagnostic methods, the proportion of culture-confirmed cases among infants has increased.

They state that there were 62 pertussis related deaths during 1997-2000 or 15 deaths per year.



And include this chart which clearly shows an increase beginning in the very early 1980s.

Another telling CDC chart showing deaths from pertussis in recent years.

Pertussis Deaths in the United States, 2004-2008

Age at onset <3 mos >3 mos Total
2004 23 4 27
2005 32 7 39
2006 12 5 16
2007 9 2 11
2008 16 2 18
Total 92

CDC, unpublished data, 2009

The CDC is also telling people that we have a vaccine failure problem, but somehow this isn’t making it into the news stories or opinion pieces.

The high numbers have been attributed in part to a possible resistance of the pertussis bacterium against the booster and vaccine. The anti-vaccination movement has also been blamed for the high rates, as Washington state ranks near the top in parental vaccination opt-outs compared to other states.

There are two major problems with blaming the outbreak on children of  vaccine refusers. The first is that adults haven’t been trotting in to get their long overdue boosters.  Only about 8% of adults have gotten a booster according to the CDC. The second is that a very large number of cases are occurring in the vaccinated population. If thousands of vaccinated children and adults are sneezing, coughing, and spreading pertussis it is hard to say that a mere 4 or 5 percent of children are the real problem.

In the real world, where do infants catch pertussis? From their family, of course, and quite frequently from their vaccinated siblings.

One point that has popped up recently is an attempt to blame the “outbreak” on the change to the acellular vaccine which came into use in the US around 1997. Since the increase in whooping cough began in the early 80s AND there are reported outbreaks in countries using the older version of the vaccine, that doesn’t exactly ring true.

The real story behind the stories is a push to use vaccine failure and vaccine refusal in adults to force vaccines into children.

A nice addition to the story brought to us by a reader of our facebook page:

> 1 Td or Tdap¶
% (95% CI)

>1 Tdap**
% (95% CI)

>1 MenACWY††
% (95% CI)

>1 HPV§§
% (95% CI)

> 3 doses HPV
% (95% CI)
Washington 2009 76.3 (70.1-81.5)   60.1 (53.8-66.2)   55.8 (49.4-62.0)   60.0 (50.9-68.5)   35.4 (27.6-44.1)
Washington 2010 82.8 (77.9-86.8)   70.6 (64.9-75.6)   67.6 (61.9-72.8)   69.3 (61.5-76.2)   45.5 (37.3-53.9)

This little chart is excerpted from the CDC stats on vaccination rates in teens in Washington state. As you can see, the coverage for getting Tdap went up substantially between 2009 and 2010. I think we could assume that the upward trend continued in 2011 and the current year, 2012. And yet…the outbreak is just roaring along. The ** on the second column indicates that 60.1% of kids had received more than one dose of Tdap since turning 10 (2009) and that 70.6% of kids had received more than one dose of Tdap since turning 10 (2010).



5 Comments on Whooping Cough – Lies, Damn Lies and Statistics

  1. Pat Robinson on Fri, 27th Jul 2012 4:25 pm
  2. This is an interesting report:

    Bass said the system has a “really good vaccination rate,” which “raises questions about the vaccine itself” and its effectiveness in preventing the disease. He and Shapley-Quinn said it’s likely the Centers for Disease Control will study the situation to examine those questions.

    SHAPLEY-QUINN SAID there’s no instance of a child who had not been vaccinated getting pertussis



  3. Peter on Thu, 16th Aug 2012 12:22 am
  4. IV do you know the incidence number from Washington according to age?

  5. Boss on Thu, 16th Aug 2012 6:32 am
  6. Hi Peter, this is what I found http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6128a1.htm which gives some info, but doesn’t include an actual chart.

  7. Leander on Wed, 22nd Aug 2012 9:40 pm
  8. In this NYT article, http://goo.gl/uxrvt Washington state health authorities were quoted as saying that the epidemic had spread so much that they were recommending doctors NOT confirm with a culture, to save money.

    I’m concerned that the lack of testing will prevent them from reporting the true number of cases seen among vaccinated people, and will therefore distort our understanding of the efficacy of the vaccine.

  9. Leander on Wed, 22nd Aug 2012 9:53 pm
  10. Is there good evidence to suggest that dTap boosters for adults WOULD protect babies?

    I know it was here on insidevaccines.com that I read about Adacel’s disclaimer: “It is unknown whether immunizing adolescents and adults against pertussis will reduce the risk of transmission to infants.”

    My understanding is that the pertussis vaccine does not prevent infection; it prevents or reduces the severity of symptoms.

    I would love some help in thinking through the risks vs benefits (for babies) of adult vaccination. Surely there is a downside in that when vaccinated adults get infected with pertussis (which the vaccine does not prevent), they can be asymtomatic, possibly having close contact with babies, instead of feeling sick and staying away?

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