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Home » Pertussis vaccine reduced length and severity of whooping cough

Pertussis vaccine reduced length and severity of whooping cough

Except for the evidence that says it's not a failure.
Except for the evidence that says it’s not a failure.

I know, there are just so many tropes and outright lies pushed by the vaccine deniers, it’s really hard for this writer to keep up with it all. But there’s one that has always bothered me, but I didn’t have quite enough evidence to lustfully debunk in my usual manner.

As has been shown in few studies, the vaccine against whooping cough (Bordetella pertussis), either  DTaP or Tdap (which also protect against tetanus and diphtheria), isn’t as effective in providing long-term protection as our expectations, based on other vaccines. Although the antivaccination cult has misinterpreted and misstated the actual numbers, an analysis of the data from the Washington State pertussis epidemic in 2011-2012 provided us with the following information:

  • Ages 5-9 unvaccinated or under vaccinated children are 6 times more likely to become infected with pertussis than fully vaccinated. 
  • Ages 10-13 unvaccinated or under vaccinated are 25 times more likely to become infected with pertussis than fully vaccinated. 
  • Ages 14-18 unvaccinated or under vaccinated  are 6 times more likely to become infected with pertussis than fully vaccinated.

In other words, not getting the vaccine made it easier to get infected with whooping cough.

But now we have even more data that should utterly squash the myth of the pertussis vaccine being useless. Yeah, I know, the vaccine deniers rarely let real evidence get in the way of their beliefs.

In a recent article by Barlow et al. (and an accompanying editorial by Mertsola) in the journal Clinical Infectious Diseases, data from the Oregon outbreak of pertussis during 2010-2012 showed that children immunized with acellular pertussis vaccine had less severe illness and significantly reduced whooping cough illness duration. So even though the vaccine is not perfectly effective (which the antivaccine cult wants to be 100% all the time), the vaccine makes an actual infection less problematic.

The researchers, led by Amy D. Sullivan, PhD, MPH, of the communicable disease services at Multnomah County Health Department in Portland, OR, thoroughly examined 753 case reports of pertussis from 1 August 2010, to 31 July 2012, to ascertain the effectiveness of acellular pertussis vaccines. Of the 753 patients, 633 were aged 6 weeks to 18 years. Moreover, 98.7% had vaccination history and illness data.

Below is the vaccination status of the group who caught pertussis :

  • 27% of the patients were not up-to-date with their vaccines
  • 46% were completely up-to-date.
  • 93% of the who had received at least one pertussis vaccination had received only the acellular version of the vaccine (as opposed to the discontinued whole cell vaccine).

The authors found that the odds of hospitalization and frequency of pneumonia were statistically decreased among all vaccinated patients, even those not up-to-date, compared to those who were never vaccinated. Furthermore, and most importantly, vaccinated (even those behind schedule) individuals were five times less likely to require hospitalization than unvaccinated individuals. Finally, vaccinated patients were 2.5 times less likely to develop a severe form of whooping cough compared to those who were unvaccinated. 

This study confirms what many of us had suspected, that even if the pertussis vaccine isn’t 100% effective, it lessens the seriousness of whooping cough. So, let’s be clear, the vaccine generally does prevent most children from catching the disease. And, if they do catch it, it’s less severe. Sounds like a win/win. 

And in case people forget, this disease isn’t some minor cough that can be ignored. Whooping cough can be a deadly 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

So anything we can do to protect our children makes sense. Because the pertussis vaccine saves lives.

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