Robert F. Kennedy Jr., secretary of health and human services, appointed eight new members of an expert panel that advises the federal government on immunization policy, including several vocal vaccine critics and one who identifies as an “anti-vaxxer.

Staff who provide data to the vaccine panel have been pushed aside, according to health officials, raising doubts about the availability of coronavirus and other vaccines.

America's vaccine policy has been set for decades, with patients, providers, scientists and insurers more or less in sync on the merits of immunizations. In the last several weeks, Health Secretary Robert F.