Robert F Kennedy Jr launches campaign challenging Biden in 2024 primaries

Member of America's most famous political family known for anti-vaccine talk and misinformation

Robert F Kennedy Jr announces his run for president on April 19 at the Boston Park Plaza Hotel, in Boston, Massachusetts. AP

Anti-vaccine activist Robert F Kennedy Jr has launched his longshot bid to challenge President Joe Biden for the Democratic nomination next year.

Mr Kennedy, a member of the country’s most famous political families who has in recent years been linked to far-right figures, started his campaign in Boston on Wednesday and likened it to the American revolution.

“My mission over the next 18 months of this campaign and throughout my presidency will be to end the corrupt merger of state and corporate power that is threatening now to impose a new kind of corporate feudalism in our country,” he said.

Self-help author Marianne Williamson is also running in the Democratic race.

Mr Kennedy, a nephew of murdered president John F Kennedy and the son of his assassinated brother Robert F Kennedy, was once a bestselling author and environmental lawyer who worked on issues such as clean water.

But more than 15 years ago, he became fixated on a belief that vaccines are not safe.

He emerged as one of the leading voices in the anti-vaccine movement and his work has been described by public health experts and even members of his own family as misleading and dangerous.

Mr Kennedy had been long involved in the movement, but the effort intensified after the Covid-19 pandemic and development of the coronavirus vaccine.

His anti-vaccine charity, Children’s Health Defence, prospered during the pandemic, with revenues more than doubling in 2020 to $6.8 million, according to filings with charity regulators.

Mr Kennedy's organisation has aimed false claims at groups that may be more prone to distrust the vaccine, including mothers and black Americans, experts have said, which could have resulted in deaths during the pandemic.

His push against the Covid-19 vaccine has linked him at times with anti-democratic figures and groups.

Mr Kennedy has appeared at events pushing the lie that the 2020 presidential election was stolen, and with people who cheered or played down the insurrection at the US Capitol on January 6, 2021.

Robert F Kennedy Jr, speaks against proposed vaccine bills during a protest rally in New York in January 2020. AP

He has repeatedly invoked Nazis and the Holocaust when talking about measures aimed at mitigating the spread of Covid-19, such as mask requirements and vaccine mandates.

Mr Kennedy has sometimes apologised for those comments, including when he suggested that people in 2022 had it worse than Anne Frank, the teenager who died in a Nazi concentration camp after hiding with her family in a secret annex in an Amsterdam house for two years.

He has at times used his family’s legacy in his anti-vaccine work, including sometimes using images of John F Kennedy.

His sister Kerry Kennedy, who runs Robert F Kennedy Human Rights, the international rights group founded by their mother Ethel, said her brother has at times removed some of the content at her request.

Ms Kennedy told AP in 2021 that her brother is “completely wrong on this issue and very dangerous".