evidence: Severe neurological disease is a rare complication of vaccine administration and typically involves a patient with immunocompromised status and/or underlying neurological disease (44,45). Varicella vaccine can, in rare cases, lead to disseminated varicella infection in immunocompromised persons with eventual meningitis, pneumonia, or hepatitis, and vaccine strain viral reactivation leading to meningitis or encephalitis (20,46). Rare cases are reported of MMR-induced measles inclusion body encephalitis in persons with immunocompromised status from the measles component of the vaccine (20,47). [...] A now-retracted paper was published in Lancet in 1998 linking autism to the MMR vaccine by claiming it causes "autistic enterocolitis". That work fueled the hysteria against vaccines, mercury, and vaccine components (2,3). The author’s status as a registered physician in the UK was revoked. Additionally, since that time a number of studies have carefully looked at the potential link between the MMR vaccine, other vaccines, mercury or other vaccine adjuvants, and autism and found no plausible scientific evidence to support this myth (2,20,57). Despite all this, people continue to cite such fears as reasons they avoid vaccinating their children.