A physician who spent decades disparaging the life-saving measles vaccine is poised to be the next head of the largest US public-health agency.

Weldon is set to appear on Thursday before the Senate Committee on Health, Education, Labor, and Pensions for a confirmation hearing where lawmakers are expected to grill him over his longtime criticism of vaccines amid rising measles and bird flu threats he would be charged with curbing.

By Ahmed Aboulenein, Julie Steenhuysen and Steve Holland WASHINGTON (Reuters) - The White House withdrew President Donald Trump's nomination of former Republican congressman and vaccine critic Dave Weldon to serve as director of the U.