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.

Seventeen vaccine experts who were dismissed from a federal advisory panel last week say they are worried that recent moves by US Health and Human Services Secretary Robert F. Kennedy Jr. will destabilize vaccine policy in the US and jeopardize access to lifesaving immunizations.

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