You’re as likely to be struck by lightning
as to have a severe reaction to a vaccine.

I was reading an article in Time last week about parents not vaccinating their children. The story was about how this phenomenon is becoming more widespread.

These kinds of stories are weird to me because vaccines are pretty safe. The risk of an adverse side effect is incredibly small. For example, the risk for anaphylaxis from the Hepatitis B Virus vaccination is around 1 in 600,000. This is about the same risk as being struck by lightning (1 in 700,000).

Of course, the article wasn’t talking about known risks. Instead, it was referring to a hypothesized link between vaccines and autism.

People proposed this link when they noticed that cases of autism and the number of vaccinations were rising at the same time. Of course, just because two things happen to occur at the same time, this does not mean they are causally linked. For example, the increase in global temperature is not related to the decrease in the world’s populations of pirates (despite what the Pastafarians say).

So how could an increased number of vaccinations cause an increase in the number of cases of autism? I have seen two ideas put forth. The first is that thimerosal is to blame. The second is that there are so many vaccinations now that we are stressing out the body’s immune system. Most likely neither idea is valid.

Thimerosal is a mercury-based preservative that used to be used in vaccines. Even though there haven’t been any good studies on the effects of thimerosal on brain development, everyone knows mercury is bad for the brain. So the idea behind thimerosal makes some sense.

Back in 2001, vaccine manufacturers decided to eliminate thimerosal from their vaccines. We would predict, then, that cases of autism should go down significantly if thimerosal was linked to autism. They haven’t. In fact, in one California study, cases have continued to climb. So thimerosal is most likely not to blame.

Another point that has been made is that there are so many vaccines now that we are stressing out our bodies’ immune systems. Again, this concern is unfounded.

Vaccines are injections of viral proteins. Our bodies see the proteins and raise antibodies to them. Then when a virus invades, we have antibodies that recognize the virus and target it for destruction.

It is the number of viral proteins that matter in terms of taxing the body’s immune system and not the number of vaccinations. All of the current vaccines put together do not have as many viral proteins as the old smallpox vaccine (150 vs. 200). So the number of vaccines is unlikely to be the issue.

What all of this means is that vaccines are probably not responsible for the significant increase in the number of cases of autism. What is responsible? No one knows for sure.

It may be that the rise just comes from all of us recognizing the symptoms more. Or it could be due to some cause we don’t know about or understand.

What we do know is that vaccines save many lives. I assume no one wants to go back to the early 20th century when polio epidemics swept the country. For example, 2,500 cases of polio ended up at one Los Angeles hospital between May and November of 1934. And in 1952, the U.S. had 21,000 cases of paralytic polio.

We can prevent this sort of thing from happening by making sure everyone is vaccinated. And yet there are people who choose to hide behind the people who take the miniscule risk of getting vaccinated.

Is this a matter of free choice? Should parents be allowed to opt out of vaccinating their children even if it risks society at large?

One idea, I suppose, is to have people who choose not to be vaccinated to sign a waiver saying they accept full responsibility for their actions. In practice this would mean that health insurance and the government would not be responsible for their children’s health care bills if they become ill with one of the diseases they refused to be vaccinated against.

And if your infant, grandma, or immuno-suppressed cousin came down with a disease these folks refused to be vaccinated against, then you could sue the un-vaccinated for damages. The common good isn’t enough to encourage these folks. Perhaps threats to their pocketbook will be.

I’m the third from left to right.I’m in my late teens in this undated photo. I’m the third from left to right. It’s very likely one of the last times I went camping as a member of the Girl Guide and Boy Scout Association of Costa Rica, which I joined when I was 11. I was very lucky growing up in Costa Rica because the association’s national campground, called Campo Escuela Iztarú, where this photo was taken, was in the hills near my house. From the backyard of my childhood home in Tres Ríos, you can see the national campground. It’s the hill in the background, dotted with a few trees. I thought a lot about this campground while I was working on our QUEST Nature Deficit Disorder TV segment about how kids nowadays in the United States aren’t spending enough time out in nature.

Every year, during the decade or so that I was a Girl Guide in Costa Rica, my fellow guides and I would trek up the steep hill, usually carrying our own sleeping bags and supplies. Once we got to the top, we chopped up wood with machetes and cooked over open fires. We woke up at the crack of dawn and showered in icy-cold water. During the rainy season, we got very wet. During the dry season, we got sunburned.

Camping took precedence over almost everything else. The day I graduated from high school I was in the middle of an international camping trip with girl guides from around the world. My parents drove up the hill, put some ointment on my sunburned ears and whizzed me over to the theater to pick up my diploma. Then they drove me back up the hill to finish the event.

My childhood home in Costa Rica, with the
campground ridge in the backgroundOur trips were always full of that sense of adventure you can only experience as a kid when you’re out in nature and away from your parents. We ran up and down the mountains, crawled in muddy pits, climbed trees and cut ourselves with our machetes. By the end of our trips we were always completely worn out. Once, I sat on my bed and fell asleep with my backpack still on my back.

But all this happiness came to a crashing halt. On Aug. 20, 1988, when I was 16, a young couple my age was murdered in a coffee field on the road to the campground. My sister and I were supposed to go camping a few days later. But my parents wouldn’t hear of it, no matter how much we begged. And who could blame them? The way he had killed his 14 victims was so cruel that it was impossible to incorporate his methods into his moniker, à la The Boston Strangler. So the press simply called him el psicópata, The Psychopath. Fear of el psicópata marked my adolescence and early adult life.

What was near-miraculous was that in time I was allowed to go camping again at Campo Escuela Iztarú. This photo of me is proof, I guess, although it doesn’t make any sense, because my parents were so fearful of everything when it came to their daughters. Perhaps they let me go because they both had good memories of the time they spent outdoors, my mother as a little girl camping all summer long in New England and my father as a teenager pedaling up and down Costa Rica’s mountains to make it to the Pacific coast by sundown. I’m so grateful to them for overcoming their fears (or not - I’m sure they had many sleepless nights). Those fleeting moments of freedom and that sense that anything is possible that I felt when I was camping are so much a part of me that I can’t even really consider them memories. So thank you, Mummy and Daddy, for letting go and letting us go up the mountain.

Watch the “Nature Deficit Disorder” TV Story online, as well as find additional links and resources. Also, please share your own photos of childhood nature experiences in our Flickr Photo Pool.

Gabriela Quirós is a Segment Producer for KQED-TV, and is the producer for this story.