A widespread conspiracy theory states that vaccinations cause autism. The theory is based on a 1998 study that attempted to establish a link between the MMR (measles-mumps-rubella) vaccination and autism. However, the study was retracted and numerous studies have since shown that there is no such link. Autism is a neurodevelopmental disorder that begins before the child is born, whereas vaccinations only occur after birth.
Another theory claims that the high-frequency radiation from 5G networks damages the brain and leads to autism. But again, there is no scientific evidence for such causality.