According to a statement just released by the California Department of Public Health, pertussis — whooping cough — is now officially an epidemic in California.

That’s right: an almost completely preventable disease is coming back with a roar in California. There have been well over 900 cases of pertussis in that state this year, over four times as many as this time last year (and 600 more suspected cases are being investigated). If this keeps up, California may see more cases in 2010 than it has in 50 years.

If that doesn’t anger and sicken you enough, then this most assuredly will: there have been five deaths this year from pertussis as well, all babies under three months of age.

Infants aren’t fully protected against pertussis until they have completed the first schedule of vaccinations, when they reach 6 months. Before then, they are vulnerable to the disease. The most likely reservoir for the bacterium? Unvaccinated people, including other children. If too many people go unvaccinated, the disease can find a host and survive long enough to infect others. If enough people are vaccinated, that chance drops. This effect is called herd immunity, and it’s the only thing that can keep this highly contagious and potentially fatal disease away from infants.

As reported in the San Francisco Chronicle:

There is no shortage of vaccines, which are provided for free to hospitals and participating counties by the state health department.

Emphasis mine. So why aren’t people getting vaccinated?

Of course, some people cannot be vaccinated due to allergies or other medical reasons. And it’s too early to say for sure if the antivax movement is behind this… but their shoulders have plenty of room for blame. [Note: some comments below are indicating that this outbreak is actually tied to the immigrant population in California. I want to be clear that I am not blaming the antivax movement for this particular epidemic, but that in many cases they can be directly or indirectly tied to lower vaccine rates. However, pending any evidence for this, which may yet be forthcoming, it is also premature to blame immigrants for this as well.] We know for a fact that in Sydney Australia, where the antivax movement was quite strong in recent years, pertussis gained strength, and several babies died, including Dana McCaffery. She was four weeks old when pertussis took her.

Four weeks.

Meryl Dorey, the head of the now-happily-defunct Australian Vaccination Network — a fringe but vocal vaccine denialist group — said all sorts of horrid things about vaccinations, all of which were incorrect. She distorted the truth, ignored evidence, and used every means at her disposal to terrify parents into not vaccinating.

Jenny McCarthy and the recently-disgraced Andrew Wakefield are also vocally spreading false information about vaccines. The result is that they are aggressively giving diseases like pertussis, measles, rubella, and even polio a chance to come back.

Vaccines work. They are one of the greatest medical inventions of all time. They have saved hundreds of millions of lives. They are inexpensive, easy to get, and may save not just your life and the lives of your children, but also those of children you’ve never even met.

This is America, this is the 21st century, and people are still dying of pertussis. It’s shameful, it’s unnecessary, and it’s completely preventable.

Syringe picture from ZaldyImg’s Flickr stream.