When Robert F. Kennedy Jr. was confirmed as America’s secretary of health and human services, neutral observers might have asked themselves: Would it be possible for a lawyer who had questioned the safety of childhood vaccinations for two decades to look at the available data and reconsider his views?

RFK Jr. has claimed measles can be treated with vitamin A and that severe infection is linked to poor diet. But many experts who spoke with ABC News disagreed.

Experts say vitamin A can mitigate measles but does not protect those who are unvaccinated from getting the disease, and RFK Jr. says immunization is a "freedom of choice."