The state of Illinois and New York City have both announced that they will join the World Health Organization’s Global Outbreak Alert and Response Network (GOARN), following Donald Trump’s decision to withdraw the US from the global body in 2025.

Illinois’s governor JB Pritzker, a Democrat, made the announcement on Tuesday, confirming that Illinois will become part of the coordinated international network dedicated to monitoring and responding to global disease outbreaks.

It is the second US state to join, after California governor Gavin Newsom, also a Democrat, made the move on 23 January following the Trump administration completing its exit from the network.

“By withdrawing from the World Health Organization, Donald Trump has undermined science and weakened our nation’s ability to detect and respond to global health threats. I refuse to sit idly by and let that happen,” Pritzker said this week.

He added: “By joining the World Health Organization’s coordinated network, GOARN, we are ensuring that our public health leaders – and the public – have the information, expertise and partnerships they need to protect the people of our state. Across our state and alongside valued partners around the world, Illinois will continue to put science, preparedness and people first.”

Illinois’s lieutenant governor, Juliana Stratton, echoed the governor’s remarks, saying: “We will always choose the health of our people over political grandstanding or misinformation, and we will remain focused on what keeps families and communities safe.”

Through its membership in GOARN, Illinois will gain direct access to global early-warning alerts and outbreak intelligence, as well as opportunities for technical collaboration and surge support during major public health emergencies. The state will also participate in international training programs, exercises and best-practice exchanges, Pritzker’s office said.

Following Illinois’s decision, New York City’s health department made a similar announcement on Wednesday, saying: “By joining GOARN, New York City gains access to a global network of over 360 institutions and organizations that respond to acute public health events with the deployment of staff and resources to affected countries.”

The city’s acting health commissioner and chief medical officer Michelle Morse also released a statement, saying: “Infectious diseases know no boundaries, and nor should the information and resources that help us protect New Yorkers.”

With an annual budget of $1.6bn and more than 7,000 employees, the New York City health department is one of the largest public health agencies in the world.

The moves from Illinois and New York City come after Trump made the decision to withdraw the US from the World Health Organization (WHO) upon retaking office last year. The US had been the WHO’s largest donor, accounting for about 18% of its total funding. Its departure led to the loss of nearly a quarter of the WHO’s workforce – about 2,000 jobs – from a total staff of roughly 9,400.

Trump’s withdrawal of the US drew widespread condemnation from medical organizations including the American Medical Association, as well as the UN.

Morse also condemned the decision, saying in January that New York City “bears an outsized risk” of infectious disease outbreaks and is “often impacted first and hardest,” particularly due to the 70 million visitors the city attracts each year.

Trump had accused the WHO of failing to act independently due to “inappropriate political influence of WHO member states”.

He also criticized the organization’s funding structure, complaining of “unfairly onerous payments” from the US, and said last January: “World Health ripped us off, everybody rips off the United States. It’s not going to happen any more.”

After the US withdrawal, both the states of Illinois and New York joined the Governor’s Public Health Alliance last October, a coalition of 15 governors – including those from Oregon and California – “committed to protecting their states from the Trump administration’s erosion of trust and dismantlement of America’s public health infrastructure”.