Kennedy's picks circumvented the usual CDC process for selecting members of the Advisory Committee on Immunization Practices. In previous administrations, career agency officials — not political leaders — vetted potential experts before forwarding them to the department for the secretary's approval.

Health Secretary Robert F. Kennedy Jr. has upended the certainty that American children will always have cost-free access to lifesaving vaccines.

He has since named eight replacements, at least two of whom are outspoken vaccine skeptics.