California Gov. Gavin Newsom said Friday that California has joined a World Health Organization outbreak response network, a move announced one day after President Donald Trump's administration completed the United States' formal withdrawal from the WHO, escalating a high-profile clash over who sets the nation's public health posture and who speaks for the country abroad.

Newsom, a Democrat, said California is the first and only state to join the WHO's Global Outbreak Alert and Response Network, known as GOARN, after meeting with WHO Director-General Tedros Adhanom Ghebreyesus on a trip tied to the World Economic Forum in Davos, Switzerland.

In a statement, Newsom criticized the administration's decision to withdraw from the WHO and framed California's decision as a backstop to federal policy.

"The Trump administration's withdrawal from the WHO is a reckless decision that will hurt all Californians and Americans. California will not bear witness to the chaos this decision will bring. We will continue to foster partnerships across the globe and remain at the forefront of public health preparedness, including through our membership as the only state in WHO's Global Outbreak Alert & Response Network."

GOARN, as described by the WHO, is a global network that coordinates expertise and partners to rapidly detect and respond to outbreaks and other health emergencies.

The U.S. withdrawal from the WHO after 80 years of membership became final Thursday, one year after Trump began the process, according to The Associated Press.

The AP report said the administration cited the WHO's performance during the COVID-19 pandemic and argued the agency needs reforms, while public health critics warned the break could reduce access to international disease intelligence and complicate response planning.

Trump's January 2025 withdrawal order stated the U.S. was leaving because of the WHO's handling of the pandemic and cited the organization's "failure to adopt urgently needed reforms" and "inability to demonstrate independence from the inappropriate political influence of WHO member states."

Newsom's office also cast California's step as part of a broader effort to build parallel state-led health coordination, citing the Governors Public Health Alliance and the West Coast Health Alliance, and pointing to a 2025 state law authorizing California to base immunization guidance on outside medical organizations rather than a federal advisory committee it described as "increasingly politicized."​

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