Reasons cited include A possible connection between the combination measles-mumps-rubella vaccine and autism (see MMR vaccine and autism) The possibility that thimerosal might cause autism (thimerosal is a mercury-based preservative used in some vaccines—see Thimerosal and autism) Use of multiple, simultaneous vaccines, given as recommended In 1998, Andrew Wakefield and colleagues published a brief report in The Lancet (see MMR vaccine and autism).