The U.S. Centers for Disease Control and Prevention and the Food and Drug Administration took part in a World Health Organization meeting to discuss flu vaccine composition, an official at the UN agency said on Friday.

The US withdrawal will not officially happen until January 2026, so there will be months of uncertainty over budgets and strategic direction at the near-80-year-old agency. Set up by the United Nations, the organization’s goals include expanding universal health coverage and coordinating the world’s response to health emergencies.

The FDA canceled a critical meeting of flu vaccine experts where officials decide which strains to target in the next vaccine. It comes amid one of the worst flu seasons in 15 years, according to the CDC.