President Donald Trump’s decision to exit the World Health Organization means the U.N. agency is losing its biggest funder.

Trump's order said the administration would cease negotiations on the WHO pandemic treaty while the withdrawal is in progress. U.S. government personnel working with the WHO will be recalled and reassigned, and the government will look for partners to take over necessary WHO activities, according to the order.

As part of a rash of executive orders completed on his first day back in the White House, President Donald Trump began the nation’s exit from the World Health Organization. Here, we explain how the withdrawal would work and what it would mean,