The main lobbying group that represents so-called pharmacy benefit managers, the Pharmaceutical Care Management Association, has drafted proposals to bring to the Centers for Medicare and Medicaid Services.

The Trump administration fired US Centers for Disease Control and Prevention Director Susan Monarez just weeks into her tenure and several senior leaders have resigned, as disputes with Health and Human Services Secretary Robert F. Kennedy Jr. over vaccine policy exploded into the open on Wednesday.

The moves come as Kennedy makes major changes to how immunizations are studied and administered in the US and paves the way for a more skeptical approach to the use of shots that prevent deadly infections.

Dr. Peter Marks, who has been the Food and Drug Administration’s top vaccine official and played a key role in President Trump’s first administration's Operation Warp Speed, stepped down Friday over conflicts with HHS Secretary Kennedy.