Carson said earlier this year, as a record outbreak of measles spread outward from California, that people should have to get vaccines regardless of their religious or philosophical objections. He was less firm when he addressed the subject on the GOP debate stage.
"Vaccines are very important. Certain ones. The ones that would prevent death or crippling," he said. "There are others, a multitude of vaccines which probably don't fit in that category and there should be some discretion in those cases."
The former Johns Hopkins surgeon did acknowledge that studies have not demonstrated any correlation between vaccinations and autism. But he took a leaf from presidential opponent Donald Trump's book in praising a delayed vaccination schedule.
"It is true that we are probably giving way too many in too short a period of time," Carson said. "A lot of pediatricians now recognize that and I think are cutting down on the number and the proximity in which those are done."