Misinformation related to immunization circulates in mass media and social media. Intentional spreading of false information and conspiracy theories have also been propagated by the general public and celebrities. Misinformation related to vaccination fuels vaccine hesitancy and thereby results in disease outbreaks. Although opposition to vaccination has existed for centuries, the internet and social media have recently facilitated the spread of vaccine-related misinformation. Unsubstantiated safety concerns related to vaccines are often presented on the internet as scientific information.