by Don Pelton

We have a number of friends here in Nevada County who will never allow their children or themselves to be vaccinated under any circumstance.

They are mostly very smart and well-educated people but, with respect to vaccines, they are making a choice that threatens all of us.

The anti-vaccine movement — of which they are a part — continues to grow and gather strength. One measure of its strength worldwide is the recent resurgence of diseases which had been mostly controlled through the use of vaccines: pertussis (“whooping cough,” on the increase here in Nevada County and statewide), measles, Hib (Haemophilus influenzae), polio, tetanus, etc.

I spoke on the phone yesterday to Sherry Dunn, the Immunization Coordinator for Nevada County, and she told me that our county is the third worst in the state for its level of immunization. Only Trinity and Mendocino counties have lower rates of immunization.

After a long and interesting conversation, she referred me to a good article in Newsweek (“Autism and the Affluent”) by Seth Mnookin, author of the recently published book, The Panic Virus.

In his article, Mnookin says:

In recent years measles outbreaks in California, Illinois, New York, and Wisconsin have cost tens of millions of dollars to contain. In 2009 six unvaccinated children in southeastern Pennsylvania were infected with Haemophilus influenzae type b, or Hib, a disease that was all but wiped out in America 20 years ago. Two of them died. In 2009 in California, there were more cases of pertussis (a.k.a. whooping cough) than in any year since 1947, before its vaccine was in widespread use. Ten children in the state died after being infected. Nine of them were younger than 6 months old.

Since its first use in the 18th century, there has always been some reluctance to submit to vaccination among a small number of people, but the roots of the modern anti-vaccine movement, as Mnookin points out, “extend back to 1998, when a British doctor claimed to have discovered a possible link (since debunked) between the MMR [mumps, measles, rubella] vaccine and autism. The following year, the Centers for Disease Control and Prevention gave more cause for concern when it recommended that pharmaceutical companies remove a mercury-based preservative from routine childhood vaccinations.” Scientific studies since that time have thoroughly disproved the link between the mercury preservative and autism.

How does the anti-vaccine movement threaten whole communities?

To understand the answer, it is necessary to understand two simple concepts:  (1) the efficacy of most vaccines, and (2) population (or “herd”) immunity.

No vaccine is 100% effective or 100% safe, and immunity conferred by a vaccine is generally somewhat less effective than a survivable experience of the disease itself (though no one seeks that “remedy”). Each individual who is vaccinated thus remains marginally at risk from exposure to the disease. And side effects may occur at a vanishingly small rate. The science of vaccination has now given us these well-established facts.

This residual risk can be further reduced by a widespread vaccination campaign that confers benefits across a high-percentage of the local population. This is called “population immunity” or “herd immunity,” and works best when there is a high level of immunization in the community. The remarkable 20th-century achievement in eradicating smallpox worldwide, for instance (after it had killed between 300 and 500 million people in that century) can be directly attributed to the wonder of population immunity.

Individuals who cannot be vaccinated (those who are too young, too old or who have already-compromised immune systems) are thus entirely dependent on population immunity. They are the most at-risk when the general level of population immunity begins to fall.

The growing anti-vaccine movement erodes the effectiveness of population immunity, and that is why we are seeing the resurgence of many diseases that were formerly under control. In Nevada County, the list of resurgent diseases most notably includes pertussis (“whooping cough”), which has been in the local news lately.

Paul Offit, M.D., in his book, Deadly Choices: How the Anti-Vaccine Movement Threatens Us All, writes about a backlash among doctors against this anti-vaccine movement:

On the other side are doctors. Weary of parents who insist on individualized [vaccination] schedules, scared to send children out of their offices unvaccinated, and concerned that their waiting rooms, packed with unvaccinated children, are becoming a dangerous place, they’re taking a stand. As many as four in ten pediatricians now refuse to see families who don’t vaccinate, causing some parents to seek the comfort of doctors or chiropractors more willing to do what they ask.

Caught in the middle are children. Left vulnerable, they’re suffering the diseases of their grandparents. Recent outbreaks of measles, mumps, whooping cough, and bacterial meningitis have caused hundreds to suffer and some to die — die because their parents feared vaccines more than the diseases they prevent.

It’s interesting to note that the anti-vaccine movement is probably amplified enormously by its use of the Internet, the likely reason it’s associated with the affluent.

I don’t know when or where this growing crisis will peak.

I hope we don’t have to return once again to the horrendous disease level of our grandparents before fear of the diseases themselves once again exceeds the fear of the vaccines available to prevent them.

In the meantime, be careful out there.