A federal judge paused the Trump administration’s decision to drastically slash the number of recommended childhood vaccines, halting the implementation of U.S. Health Secretary Robert F. Kennedy Jr.’s unprecedented change to national immunization policy.

The decision Monday by Judge Brian Murphy of the U.S. District Court for the District of Massachusetts also stays the appointments of 13 members Kennedy selected for the Advisory Committee on Immunization Practices, which helps determine which vaccines are covered by insurance and provided for free for some children.

The order granting the stay to the American Academy of Pediatrics and other medical groups is a temporary victory over Kennedy’s remaking of federal vaccine policy, which includes downgrading the status of COVID-19 shots for certain groups, while the case plays out in court.

Kennedy last June reconstituted the ACIP panel with his own selections critical of vaccines after removing all its previous members. The changes threw U.S. vaccine policy into disarray, with some states codifying previous immunization schedules that would differ from the federal government.

The advisory panel was scheduled to meet this week on Wednesday and Thursday at the U.S. Centers for Disease Control and Prevention headquarters, but Murphy said “ACIP as currently constituted cannot meet” this week.

“Plaintiffs have demonstrated that the harms described above will continue to arise out of further ACIP actions,” Murphy wrote. “While Defendants argue that it is merely ‘speculative’ that ACIP will take any votes at a future meeting, the Court finds the evidence both credible and compelling that a vote is likely at ACIP’s upcoming meeting.”

Murphy said it “would be inappropriate” for the court either to block ACIP from meeting, or to “effectively select-by-veto a different ACIP.”

A spokesperson for the U.S. Department of Health and Human Services said the ACIP meeting is now postponed.

“HHS looks forward to this judge’s decision being overturned just like his other attempts to keep the Trump administration from governing,” Andrew Nixon, an HHS spokesperson, said in an email.

Kennedy has long been a vaccine critic and has made radical changes to U.S. immunization policy, often playing up fears about their vaccine and debunked links to autism. During his tenure as HHS secretary, the U.S. moved to shrink the number of recommended shots for children. It’s also curbed access to COVID shots for healthy young people and pregnant women.

It’s the first move from a court to rein Kennedy in on vaccines. The decision paused the changes to the childhood vaccine schedule that HHS made in January. Prior to the January change, ACIP removed the universal newborn recommendation for hepatitis B vaccines and stopped recommending COVID shots for kids. More than a dozen states filed a separate challenge in February over changes to the vaccine committee and the childhood schedule.

A lawyer for the plaintiffs, Richard Hughes of Epstein Becker Green, celebrated the decision Monday.

“This is a significant victory for public health, evidence-based medicine, the rule of law, and the American people,” Hughes said in a statement.

Hughes in a press briefing after the decision warned that if ACIP decides to proceed with this week’s meeting, “that will not constitute an ACIP meeting.”

“Our expectation and our hope would be they would comply with the judge’s order,” he said.

The case is American Academy of Pediatrics v. Kennedy, D. Mass., No. 1:25-cv-11916, order entered 3/16/26.

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(With assistance from Anna Edney.)

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