President-elect Donald Trump said he’s tapping Robert F. Kennedy Jr. to run the Department of Health and Human Services, a move that would elevate a prominent vaccine skeptic and pharmaceutical industry critic to a top role on federal health policy.

Vaccine stocks have struggled since RFK Jr.'s appointment to health secretary, with Moderna and Pfizer seeing the deepest losses.

Kennedy Jr. was himself a Democrat until he campaigned in this year's presidential campaign as an independent focused on health care. But he abandoned the race after receiving a pledge from the Republican Trump that he'd be given a high-ranking position in health policy should Trump return to power.