() Leaders at the Centers for Disease Control and Prevention walked out Thursday in protest of the removal of Director Susan Monarez.

Crowds of supporters gathered outside CDC headquarters in Atlanta to show support for the employees after the controversial decision.

Monarez was fired less than a month into her role, reportedly for refusing to remove agency officials and refusing to restrict scientifically proven vaccines.

At least four CDC leaders also resigned in protest, including infectious disease physician Demetre Daskalakis, who posted his resignation letter online.

“After much contemplation and reflection on recent developments and perspectives brought to light by Secretary Robert F Kennedy Jr, I find that the views he and his staff have shared challenge my ability to continue in my current role at the agency and in the service of the health of the American people,” he wrote.

The White House says Monarez was fired because she was not aligned with the president’s agenda.

Health and Human Services Secretary Robert F. Kennedy Jr. appointed Jim O’Neill as interim director. Having served as Kennedy’s deputy, O’Neill is a biotech investor with no background in medicine and has promoted COVID treatments not backed by research, including the use of ivermectin.