Watch: Key moments from RFK Jr's heated Senate hearing

Robert F Kennedy Jr faced questions on Covid deaths, vaccines and his record as US health secretary during an often heated Senate hearing.

When asked whether he accepts that one million Americans died from Covid, he responded: "I don't know how many died... I don't think anybody knows".

Last week the director of the Centers for Disease Control and Prevention, Susan Monarez, was dismissed, which led to other CDC leaders resigning.