Oct 6 (Reuters) - A lawyer for the Trump administration told a federal appeals court on Tuesday that a judge had improperly hamstrung an influential vaccine advisory panel by blocking Health Secretary Robert F. ⁠Kennedy Jr.'s handpicked appointees from serving on it.

US Justice Department attorney Matthew Zorn argued at a hearing before the 1st US Circuit Court of Appeals in Boston that the judge's ruling was preventing the ⁠Advisory Committee on Immunization Practices from meeting due to concerns that any new appointments Kennedy made to it could also be blocked.

"We're asking the court to vacate the ⁠order on the appointments so that the secretary can ‌reconstitute the committee and get it back to work," Zorn said.

Kennedy, an anti-vaccine activist picked by President Donald Trump last year to head the US Department of Health and Human Services, removed and replaced all 17 independent experts who previously served on the panel, which makes recommendations on vaccine policy to the Centers for Disease Control and Prevention.

That action formed the basis of the lawsuit by the American Academy of Pediatrics and other medical groups, which also sought ‌to block other shifts in vaccine policy under Kennedy.

US District Judge Brian Murphy in a March 16 order concluded that Kennedy, ​in picking ‌new members, did not comply with the Federal Advisory Committee Act, which requires ‌such advisory panels to be balanced, and instead picked "distinctly unqualified" individuals to serve on the committee that is supposed to be composed of experts on vaccines and immunization.

The Trump administration ⁠contends that portion of Murphy's order has deprived ACIP of a quorum needed to issue recommendations ‌on flu shots and other vaccines because ⁠any newly appointed members would likely require court approval.

Some members ​of the three-judge appeals court panel on Tuesday raised concerns ‌about how Murphy had crafted his order, which blocked 13 appointees from serving. Chief US Circuit Judge David Barron said it lacked any explanation for why blocking Kennedy's appointees was legally authorized or justified.

"It's hard to know precisely what harm this relief was designed to address," he said.

But Andrew Pincus, ​a lawyer for the plaintiffs, urged the court to leave it in place, saying Murphy's decision ‌to ‌block 13 of the panel's members from continuing to serve provided "important protection for America's public health."

Murphy in his order also blocked the CDC's January 5 move ‌to cut the number of routinely ​recommended childhood vaccinations and set aside votes ACIP had taken under Kennedy's watch, including to downgrade recommendations for hepatitis B vaccines for newborns and COVID-19 shots broadly.

The Trump administration opted against appealing those portions of that ruling by Murphy, an appointee of Democratic President Joe ⁠Biden, and instead focused narrowly on his decision blocking the 13 appointees to the vaccine panel.

Since Murphy ruled, ACIP ‌has not met, canceling two meetings so far. Another, set for October 21-23, would likely also be canceled if the committee is not reconstituted ​before then.

(Reporting by Nate Raymond in Boston; Editing by Bill Berkrot)