Vaccines do not cause autism. Do people who receive vaccines have autism at higher rates than those who do not receive vaccines? No. Do geographic areas that stop giving vaccines containing thimerosal see a drop in the incidence of autism? No.
What we do see in regions that stop immunizing is higher rates of vaccine-preventable diseases - among the electively unimmunized families themselves, people who cannot be immunized for a true medical contraindication or the small number of people in whom the vaccine did not "take" (no vaccine is 100 percent effective).
When families decide not to immunize their children, for what I can appreciate are the most loving albeit misinformed of reasons, they expose their children to the sometimes truly awful effects of vaccine-preventable diseases, including death, and expose the wider community who has not shared their decision.
Regarding an extended or alternate vaccine schedule, the goal of the recommended immunization schedule is to protect children from the most vaccine-preventable diseases at the earliest ages when the vaccines are effective in accordance with research on vaccine safety and effectiveness at specific times. When a parent and physician follow some alternate program, they are not backed by research, they leave the child vulnerable to preventable disease and death, and they endanger the wider community. At any visit where the opportunity is missed to give a recommended vaccine, there is a chance that the family will not follow up as intended, leaving the child unprotected for an extended period. See www.cdc.gov/vaccines; www.cispimmunize.org and www.immunize.org.
Director, Immunization Education
American Academy of Pediatrics