It’s challenging to report on an illness such as autism, which scientists and doctors are only beginning to understand (the disease was described in the 1940s) and over which there is so much debate.

There is even disagreement around the question of whether or not there has been a real increase in the number of children being diagnosed with autism in California. In our TV segment, we interview psychologist Ron Huff, director of clinical services at the Alta California Regional Center in Sacramento. In the mid-1990s, Huff sounded the alarm about an increase in the number of reported cases of autism in California. (Through California’s 21 regional centers the state’s Department of Developmental Services offers services to children and adults with developmental disabilities).

“In 1996 I asked the Department of Developmental Services to pull some raw data off of their statewide electronic information system. And when I saw that data it was obvious that there were a lot more kids in our system with autism than anyone else had expected,”Huff told QUEST. “By 1999 the (California) legislature decided to have the department do a formal study of the number of people who were entering the system with autism. So we looked at about 11 years of data and recognized that there was a 300 plus percent increase in the number of kids coming in with autism.”

Since then, researchers have vigorously been debating whether or not there is a true increase in the number of cases. Huff believes that at least part of the increase is a true increase, in other words, that not all of the increase can be explained by factors such as more accurate diagnosis of autism, increased awareness or better availability of services. But other researchers like Kaiser Permanente epidemiologist Lisa Croen feel there isn’t enough information to conclude that even part of the cases are due to a true increase.

“Unfortunately, I don’t think we really have the data, and no one really has the data right now to answer that question adequately,” she told QUEST. But in her view, whether or not there’s a true increase, there is indeed a crisis afoot. “It goes without question that there are definitely more people being diagnosed with autism today than ever before and that is a really big public health crisis. Estimates across the country are that one in 150 children at about 8 years of age will have a diagnosis of autism. So whether or not the increase, or how much of this increase, is really due to a true increase in occurrence, the question now is what’s causing this and what are the risk factors and that’s what we really have to concentrate on.”

The research looking into factors other than genes is just beginning. The Centers for Disease Control have launched a large epidemiological study called SEED that seeks to answer the question of what the environmental causes of autism are. When researchers talk about “environmental factors” they mean this very broadly. These factors include, for example, the age of the parents. For our TV story we filmed Meghan Wallace, a four-year-old with an autism diagnosis who is participating in SEED. In Northern California, Kaiser Permanente is overseeing the research. Both children with and without autism are being enrolled. “There really has never been a large, robust, well-designed epidemiologic study that can adequately study the many possible risk factors for autism spectrum disorders,” said Lisa Croen, who is one of the principal investigators on SEED.

At the same time, U.C. Davis’ M.I.N.D. Institute is carrying out a smaller study into the causes of autism. It’s called MARBLES and it’s funded by the EPA and the National Institute of Environmental Health Sciences. By studying pregnant women, MARBLES principal investigator Irva Hertz-Picciotto hopes to find out if there are any risk factors for autism that happen during pregnancy. In our TV story, we followed M.I.N.D. Institute personnel as they visited one of the families in the study. They had followed the mother through her pregnancy and delivery and were now taking samples from her six-month-old boy. The researchers collected everything from his dirty diapers to dust from the family’s rug. In between, they asked the mom about her family’s use of pesticides and cleaning products.

Hertz-Picciotto’s research stemming from another M.I.N.D. Institute study has already pointed to a connection between autism and pesticides. In May of 2008, she and her colleagues reported at the International Meeting for Autism Research in London that mothers of autistic children were twice as likely as mothers of children who didn’t develop autism to report that they had used household insecticides and pet shampoos for fleas or ticks. They reported using these products during a period between three months before conception and the first year of the child’s life. Other risk factors are also starting to emerge. A study by Lisa Croen and colleagues reported that paternal and maternal age are risk factors for autism. “What we found was for every 10 years of increase in the age of a mother or a father, the risk of autism went up by about 20 or 30%,” Croen told QUEST.

Both the SEED and the MARBLES studies are looking at the question of whether or not childhood vaccination is a risk factor for autism. This is another issue that we talk about in our TV story. Concerned about guaranteeing that infectious diseases don’t reemerge, public health officials at agencies like the CDCs state that research doesn’t bear out an autism-vaccine connection. But UC Davis’ M.I.N.D. Institute is taking a more nuanced approach to the question. Based on new findings by their researchers showing that the immune systems of autistic children are different than those of typically developing children, the Institute suggests that a small number of children may respond to vaccines in an atypical way. They quickly add that there isn’t yet a way to determine who those children might be. Studies like SEED and MARBLES might help elucidate this and other questions about what remains a mysterious disease.

Watch the “Autism: Searching for Causes” TV Story online, as well as find additional links and resources.

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.