The administration of U.S. President Donald Trump has told global vaccine group Gavi to phase out shots containing the preservative thimerosal as a condition of providing the group with funding, a U.S. official and a Gavi spokesperson said.

The request is the latest sign of efforts by the Trump administration to influence health policy globally.

Anti-vaccine groups, including one founded by U.S. Health Secretary Robert F. Kennedy Jr., have for decades ?claimed that thimerosal, ?a mercury-based preservative used in vaccines, is linked to autism and other neurodevelopmental disorders, despite many studies showing no ?related safety issues.