As a retired pediatrician and former state health officer, I wish to respond to the guest column by Dr. Edward Fogarty, "A proposal on vaccinations."

I regret the fact that Fogarty has a child with autism, a disorder that produces a terrible stress on families.

I do not agree, however, that the recent Hanna Poling case established a causal link between vaccinations and autism. I believe that the fact that Hanna has a genetic "mitochondrial disorder" helps confirm that genetic factors do play a role in at least some children with autism.

The Simpsonwood Transcript referred to in the column resulted from a meeting of scientists in June 2000 to review data regarding a possible role of the mercury containing preservative Thimeorsal in some vaccines and possible adverse effects in children. No causal effect of Thimerosal in regard to autism has been widely accepted, but a decision to no longer use the preservative in vaccines was a wise one.

One of the reasons for using "booster" doses of vaccines is to take advantage of a memory feature of the immune system known as an "anamnestic response," in which repeated doses of a vaccine push antibody levels up to where they last for years. I am not sure how Fogarty proposes to use the antibody titers, as a titer showing adequate immunity at a particular point in time may later fall to less than adequate levels.

Despite Fogarty's negative view of the federal government and pharmaceutical industry, the State Health Department and many physicians who administer vaccines depend upon the American Committee on Immunization Practices and the Centers for Disease Control to develop science-based guidelines for vaccine administration.