Mr Trump, who is the current frontrunner among the Republican presidential hopefuls, claimed autism rates have risen into an “epidemic” over the last few decades that is “totally out of control”.

“Autism has become an epidemic. 25 years ago, 35 years ago, you look at the statistics, it’s not even close. It has gotten totally out of control,” he said.

The property developer and TV personality said he had evidence of a relationship between autism and vaccinations after seeing an employee’s child diagnosed with the disability following an adverse reaction to a vaccine.