President Donald Trump used one of the flurry of executive actions that he issued on his first day back in the White House to begin the process of withdrawing the U.S. from the World Health Organization for the second time in less than five years — a move many scientists fear could roll back decades-long gains made in fighting

President Donald Trump announced Monday he is withdrawing the US from the World Health Organization, a significant move on his first day back in the White House cutting ties with the United Nations’ public health agency and drawing criticism from public health experts.