Look carefully at study connecting upswing in autism to vaccinations
By Dr. Anthony Policastro
Nanticoke Memorial Hospital
About five years ago, I published an article on vaccines and autism. The topic is now in the news again. For that reason it makes sense to update that article.
Many things occur coincidentally. We sometimes try to tie coincidence together as if there was a relationship. For example, you seem to miss all the traffic lights when you are running late. You may not be missing any more than usual. However, you are paying attention to them more. So it looks like there is a relationship.
That same thing happens in medicine. It gives rise to many rumors about medical related items. The biggest example of this is teething. Between six months and 18 months of age, children cut 12 new teeth. That is about one per month. They tend to be a little irritable when that happens. It may cause softer stools, but not diarrhea. It may cause a temperature of about 100 degrees, but not any higher.
However, parents frequently think all sorts of illnesses are due to fever. One may ask why they do that. It is related to coincidence. At about six months of age, infants lose the protection against infection that they received from their mother across the placenta. Between six months and 24 months of age, they begin to come down with a series of infections to build up their own immune system.
The result is a pattern. They have 72 hours of illness. This is followed by 10 days of wellness. Then they get sick for another 72 hours. Thus, every two weeks they have some kind of infection. During this period, they are cutting one tooth per month. The result is a myth that teething causes all sorts of symptoms. It is not true. It is just a coincidence.
There are some things that change with time. For example, the curvatures that many infants have in their legs improve over time. At one time we treated these curves with braces. We then found out that they got better just as fast without braces as they did with braces. The improvement was a coincidence.
There are a lot of other medically related issues that are based purely on coincidence. A recent example involves childhood autism. Autism is a complex developmental disorder. The signs and symptoms of it are too complicated to cover in a brief article like this. It is likely that several different things cause the symptoms. However, one fact that has been noted is that autism is on the increase.
Other things are also on the increase. A few years ago a group in England led by Dr. Wakefield suggested that the increase in autism might be related to the increased use of measles-mumps-rubella vaccine. Then in 1999, California's Department of Developmental Services published a report that their caseload for autism had risen significantly over the last 20 years.
At that point Dr Wakefield wrote a letter to the editor suggesting that this proved his point. Then the media picked up his letter and starting suggesting that autism was related to measles-mumps-rubella vaccine.
The result was that many people believed there was a relationship between the two events because of what they saw on the news. The media ignored the fact that later studies in both England and Sweden failed to show any relationship between the two.
In March 2001, a group of researchers looked carefully at the California data. They created a graph that showed three items. The top line showed the percentage of children that received the vaccine by 24 months of age. The middle line showed the number of children that received the vaccine by 17 months of age. The bottom line showed the number of cases of autism.
The graph showed two things. The first was that the rise of cases of autism began in 1985. Measles-mumps-rubella vaccine had started long before 1985. It did show a climb later on. However, that did not occur until 1988. That was a full three years after the number of cases of autism began to increase. Thus, there was time wise relation to the increases.
The second thing that the graph showed was that the vaccine rates increased about 14 percent. During the same period the number of cases of autism increased by 373 percent. Again there appeared to be no relationship to the two items.
The new culprit is thimersol mercury. It is present in small amounts in vaccines that we use. Over the years the amounts have decreased. However, there are individuals who are convinced that it is the cause of autism. Their logic is that since no one has proved that there is no relationship, then there must be one.
I don't know if the future studies will show that there is a relationship or not. What I do know is that being convinced in the meantime that there is a relationship without evidence to support that also does not make sense.
The major concern right now is that people might believe the relationship to be a fact and stop having their children immunized. Control of diseases that we give immunizations for has been one of the great public health stories in this country. In 1938, measles, diptheria and whooping cough were all in the top ten killers of children. Until the 1950s, polio left many children crippled for life.
We need to be sure that we do not assume vaccines are bad and go back to the old days of death and disability based upon what could be a coincidence.
Dr. Anthony Policastro is medical director at Nanticoke Memorial Hospital.