In 1998, the measles-mumps-rubella (MMR) vaccine was the subject of controversy in the UK when Andrew Wakefield et al. [16] reported on twelve children who developed symptoms of autism spectrum disorder soon after they had received MMR. The interpretation section of this study was later retracted in 2004 by ten of Wakefield's coauthors, and subsequent large studies concluded that there was no evidence of a link between MMR and autism [17]. Early thiomersal exposure was also hypothesized to be associated with neuropsychological deficits in children, although this link was not supported in a study of 1047 children aged 7 to 10 years [18]. Nevertheless, in 1999, the American Academy of Pediatrics and Centers for Disease Control and Prevention requested removal of thiomersal from all pediatric vaccines, and this ethylmercury-containing preservative was no longer used in routine childhood vaccines in the U.S. as of 2001. Although the autism link has been refuted, the need for stringent safety monitoring in the development of all vaccines remains, particularly those that may be given to newborns.