Maryn McKenna makes a critical, yet neglected point about the recent whooping cough (pertussis) outbreaks that have been hitting California–one that emphasizes that vaccination not only protects the vaccinated, but everyone else:

Between a day job as Scary Disease Girl and a childhood spent moving between continents, I am pretty much the most vaccinated person on the planet. I’d had my full series of pertussis vaccinations as a child. Surely I was protected?

Actually, no — and unless you’ve had a booster, neither are you. The immunity created by the 5-dose childhood series wanes over time; by the age of 12, even fully vaccinated people are vulnerable to pertussis again. Since 2006, the Advisory Committee on Immunization Practices has been recommending a single additional pertussis (Tdap) booster for anyone between the ages of 11 and 64. That may seem like overkill — adult cases of pertussis in previously vaccinated people are often milder than the child version; after all, I survived my bout. But as with so many vaccines, the beneficiary here isn’t just the adult taking the booster. Even more, it’s the more vulnerable person to whom that adult might pass the disease: an elderly person with age-related immune decay; someone with a chronic disease; an infant too young to be vaccinated. In those people, the disease can and does kill — as it did an 18-day-old infant, Nelyn Baker, whom I wrote about in 2004.

Let’s not forget the Mad Biologist’s Pentultimate Postulate of Vaccination: Effective vaccination is not about protecting you, it’s about protecting other people from you.

As I noted about the Streptococcus pneumoniae vaccine (‘PCV7′):

The PCV7 vaccine confers immunity to the seven most common types of Streptococcus pneumoniae, a bacterium that causes pneumonia (worldwide, S. pneumoniae is the leading killer of children under five, not the Big Three that the Gates Foundation focuses on. Just sayin’). In the U.S., starting in 2000, children under five were vaccinated against S. pneumoniae, which led to a 94% drop in cases of invasive pneumonia in young children three years after the introduction of the vaccination (my thanks to the Notorious K.A.T. for pointing me towards the reference).

But there was an unanticipated side effect of the PCV7 vaccine–and it was a good thing (sometimes the ‘law’ of unanticipated consequences works out well): invasive pneumonia dropped by two-thirds among the elderly during that same time.

Elderly people didn’t receive the vaccine. Only the young kids were vaccinated. And the pattern in the elderly was exactly as one would expect: the amount of invasive pneumonia caused by the S. pneumoniae that the vaccine protects against, dropped, while infections due to S. pneumoniae not found in the vaccine remained essentially constant.

This is why I’ve written before on this blog that the grandchildren are killing their grandparents (because they are). It’s also why I have, tongue-in-cheek, formulated the Mad Biologist’s Pentultimate Postulate of Vaccination.

I’ll just end by noting a gruesome irony. Many anti-vaxxers are worried about ‘toxins.’ Well, pertussis produces several dangerous, if not deadly, toxins–no scare quotes there–and they aren’t imaginary.