Many scientists at the federal health agencies await the second Donald Trump administration with dread as well as uncertainty over how the president-elect will reconcile starkly different philosophies among the leaders of his team.

Donald Trump has picked vaccine sceptic and former independent presidential candidate Robert F Kennedy Jr as his health secretary, as the president-elect continues to build his new administration. Kennedy, commonly known by his initials RFK Jr, has a history of spreading health information that scientists say is false.

Kennedy has made false claims about childhood vaccines and the COVID vaccines that public health experts credit with ending the pandemic and saving millions of lives.