Robert F. Kennedy Jr.’s decision to overhaul a key committee on vaccine policy has left the country’s vaccine infrastructure “critically weakened,” former members of the group said in a piece published in JAMA on Monday.

Fiona Havers, who oversaw CDC respiratory virus data, told colleagues she no longer had confidence the data would be used objectively to set vaccine policy.

Health Secretary Robert F. Kennedy Jr. announced last week that he had removed every member of an independent panel key to vaccine policy and access in America. After removing the 17 members of the panel, Kennedy announced eight new names, many of whom have been skeptical of vaccines.