Donald Trump has appointed Robert Kennedy Jr, a prominent vaccine conspiracy theorist, to chair a commission on "vaccination safety and scientific integrity".

Mr Kennedy accepted the request at Trump Tower where they talked about vaccines and immunisations, according to the President-elect’s press secretary Sean Spicer.

Both men share a belief that there is a link between vaccines and autism. The theory has been repeatedly debunked and the Center for Disease Control said on its website that there not "any link" to the neurodevelopmental disorder.

"President Trump has some doubts about the current vaccine policies and he has questions about it," said Mr Kennedy.

"He says his opinion doesn’t matter, but science does matter. And we ought to be reading the science, and we ought to be debating the science."

The President-elect tweeted about the supposed link as early as 2012, around the same time he claimed on social media that climate change was a hoax invented by the Chinese.

"I am totally in favour of vaccines," Mr Trump said during a primary season debate in 2015.

"But I want smaller doses over a longer period of time. Same exact amount, but you take this little beautiful baby, and you pump—I mean, it looks just like it’s meant for a horse, not for a child, and we’ve had so many instances, people that work for me. ... [in which] a child, a beautiful child went to have the vaccine, and came back and a week later had a tremendous fever, got very, very sick, now is autistic."

Mr Kennedy, the eldest son of senator Robert Kennedy, is also an environmental advocate, and told reporters that Mr Trump had told him he was “a very strong supporter“ of solar energy. During his meeting, executives from oil company BHP were also at Trump Tower.

But more recently Mr Kennedy has devoted his time to the issue of vaccines, writing a book and producing a documentary on the subject.

"They get the shot, that night they have a fever of a hundred and three, they go to sleep, and three months later their brain is gone," Mr Kennedy said at one screening in 2015 in California.

"This is a holocaust, what this is doing to our country."

He later apologised for the comment.

Asked at Trump Tower what his famous late relatives would have thought of President Trump, he replied: “I think that President Trump can be any kind of President he wants to be.