BOSTON, March 16 (Reuters) - A federal judge on Monday

blocked key parts of Health Secretary Robert F. Kennedy Jr.'s

effort to reshape U.S. vaccine policy, including a move to

reduce the number of shots routinely ​recommended for children.

U.S. District Judge Brian Murphy in Boston sided with the

American Academy of Pediatrics and other medical groups, which

said health regulators had acted unlawfully to carry out

Kennedy's agenda of upending immunization policies and warned

the changes will reduce vaccination rates and harm public

health.

Vaccine makers have grown increasingly wary of U.S. vaccine

policy, including the makers of mRNA COVID-19 vaccines Pfizer ( PFE )

, BioNTech, and Moderna ( MRNA ). Companies

that make other shots on the U.S. childhood vaccine schedule

include Merck ( MRK ), Sanofi and GSK.

As Kennedy's policies have taken hold, pediatricians have faced

parents increasingly skeptical about vaccines and medical

treatments, while nearly a dozen states have begun considering

legal changes that would relax vaccine requirements for school

enrollment.

The judge, who was appointed by Democratic President Joe

Biden, has earned the scorn of Republican President Donald Trump

and his allies for repeatedly blocking administration

initiatives, including core parts of Trump's hardline

immigration agenda.

The plaintiffs had argued the U.S. Centers for Disease

Control and Prevention acted unlawfully when on January 5 it cut

the number of routinely recommended childhood vaccinations to 11

and downgraded the immunization recommendations for six

diseases, including rotavirus, influenza and hepatitis A.

They also challenged Kennedy's decision last year to remove

and replace all 17 independent experts who previously served on

the Advisory Committee on Immunization Practices, or ACIP, which

makes recommendations that shape U.S. vaccine practices and

insurance coverage.