Robert F. Kennedy Jr.’s nomination to be the nation’s top health official is uncertain after a key Republican joined Democrats to raise persistent concerns over the nominee’s deep skepticism of routine childhood vaccinations that prevent deadly diseases.

During his Senate confirmation hearing, Kennedy claimed he is not against vaccination, contrary to decades of public comments.

Kennedy, a Democrat who ended up supporting Trump in the 2024 presidential campaign, faced a confirmation grilling Wednesday over his controversial views -- on everything from vaccines to abortion -- that have both Republicans and Democrats raising concerns.