Kennedy has been criticized for making false medical claims. He has also vowed to purge the U.S. Food and Drug Administration.

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

Donald Trump nominated Robert F. Kennedy Jr., a vaccine skeptic and harsh critic of federal health agencies, to be his Secretary of Health and Human Services. Trump announced the nomination in a post on Truth Social.