I found some interesting material on primitive reflexes which may tie into your theory. Again, from Chiropractic : The Anatomy and Physiology of SacroOcciptal Technique by Jonathan Howat, DC, DICS, etc. This info has been taught and developed by Peter Blythe, Diector of the Institute for NeuroPhysiological Psychology.
Page 317 : "Neurological developmental delay deals with primitive, transitional and postural delays. Every intra-uterine primitive and transitional reflex had a purpose. Once achieved it should be inhibited by a higher part of the developing brain, this allows reflexes to become established which will advance the development of the nervous system, movement and sensory integration. If the reflex does not develop or is never completely suppressed growth will be hampered, an immature central nervous system will result, with a poor response to an increasingly complex learning environment."
So perhaps, the injections could possibly interfere with the correct development and suppression of reflex patterns?
Why don't you write to one of these experts in SOT or Peter Blythe and discuss this idea?
More of interest : My son showed some autistic like symptoms early on. Remember,he had a terrible case of well - documented EBV at age 5/1986. Extreme sensitivity to all clothing - wore the same pair of shorts every day to school in the 4th grade. Slow language development. Poor fine motor/ writing. Anxiety, didn't do any homework until 5th grade. Had panic attacks going to school. Had an IEP - with pull out to the Resource Room program. Did not travel well or adjust to new situations. Was all of this related to EBV? Or some birth trauma? vaccines? We had a happy ending as he started doing very well about age 12, despite developing scoliosis, migraines, asthma.
He ended up graduating valedictorian from large high school, then honors in computer science from a Univ. of Calif. Has a very successful business, wife, and 2 kids. But must be very careful with stress. Has chronic throat clearing. A wonderful, intuitive, bright person. But what a tough journey. Wow.