Sorry, I got a bit sloppy with my description, I tried to fix, but unkle found my explanation confusing. I will try to give an explanation again.
Case control and cohort studies were performed. The purpose of these studies is to separate out the effect of vaccine administration from other affects things that may influence the rate of diagnosis of autism. One thing we would want to separate out is the effects on the diagnosis of autism from changes in environment, culture, or medical practice overtime, or different countries. Those would be called confounding variable‘s. These studies allow us to look at the effects of vaccines when those confounding variables are basically held constant.In these studies, The confidence intervals-were small and crossed 1.
What this means is that When these confounding variables were held constant, there was no correlation.
These studies actually used to look at causation.
Depending on what confounding variable‘s are lumped in you can make some thing have either a positive or a negative correlation. As an example in the United States Obesity prevalence has a positive correlation with life expectancy., so therefore the heavier we are the longer we live. That is true if you look over the past 60 years and just look at life expectancy that year and average BMI that year. I think we can agree that Obesity does not in fact increase longevity, and if we control for the other changes that occurred over this time period, that effect reverses.
Can you lump in vaccines with some confounding variable‘s and create a correlation with autism, either positive or negative? Yes, as is the case with everything else.
When you learn that when the confounder is stripped out, the correlation disappears,
As an aside, I get tested regularly at work, just came back positive. No symptoms at present. I have heard(from either an epidemiologist or hospitalist, don’t remember which) that exercising while infected may increase risk of, and effect of, long term symptoms. I will do some research to determine if I should take a little time off. Fortunately, I was kind of due for a down week.