The United States officially withdrew from the World Health Organization (WHO) on Thursday, one year after President Donald Trump announced his intention to leave the agency.

The administration said the decision was driven by concerns that the WHO mishandled the corona virus pandemic, failed to implement necessary reforms and was subject to undue political pressure from some member states.

The Washington Post reported that the withdrawal has stunned international health experts and officials. The United States has long been an influential member of the 194‑member organization, played a key role in its founding in 1948 and has been a major financial contributor throughout its history, the report said.

“Withdrawal from the World Health Organization is scientifically irresponsible,” said Ronald G. Nahass, president of the Infectious Diseases Society of America (IDSA). “This move fails to take into account the inherent nature of infectious diseases. Global cooperation is not a luxury; it is a biological necessity.”

When the withdrawal was announced, the U.S. Department of Health and Human Services said the country would continue to lead on global health. The department said that leadership would be pursued “through existing and new partnerships with other countries, the private sector, nongovernmental organizations and faith‑based institutions.”

A senior Health and Human Services official told reporters that future U.S. global health efforts will be anchored in federal agencies such as the Centers for Disease Control and Prevention, the National Institutes of Health and the Food and Drug Administration. The official noted that these institutions currently operate in 63 countries and maintain bilateral agreements with hundreds of governments.

The WHO has said the United States must meet its outstanding financial obligations before a withdrawal can take effect. The organization’s executive board is also scheduled to consider the matter at its February meeting.

Public health experts are raising questions about how the United States will sustain its global public health leadership outside the WHO framework and what the move will mean for international coordination on future health emergencies.