SACRAMENTO (CBS/AP) — Robert Kennedy Jr. is apologizing for describing the number of children injured by vaccines as “a holocaust” during an event last week.

The nephew of President John F. Kennedy and son of former U.S. Attorney General Robert Kennedy used the term at a Sacramento screening of the film “Trace Amounts.” The movie links autism to a vaccine preservative, even though the medical community says such claims have been scientifically disproved.

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Kennedy says in a statement Monday that he was struggling for a way to convey the effects of autism on children and their families.

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Kennedy opposes a California bill that would limit vaccination waivers for school children. It has generated such an acidic debate that some opponents have compared the proposal’s author online to Adolf Hitler.

Thursday marks Holocaust Remembrance Day.

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