Several leading cancer organizations have signed a letter urging President Trump to reconsider his plan to withdraw the United States from the World Health Organization (WHO), the United Nations agency that promotes public health and oversees international health efforts, such as coordinating vaccines for the flu and COVID-19. At least four international HIV groups based in the United States have also spoken out against leaving the WHO.

The National Comprehensive Cancer Network (NCCN) spearheaded the letter that was signed by groups representing patients, researchers and caregivers. The letter points out that cancer, which remains the second-leading cause of death worldwide, is on the rise in developing nations. In fact, 75% of all cancer deaths worldwide are in low- and middle-income countries, according to the letter.

Those countries rely on U.S. support to fight cancer. The Unites States helps that cause in numerous ways, including reducing preventable cancers by promoting healthy diets, exercise and vaccinations.

The letter notes that initiatives to fight cancer globally—for example, the goal of battling childhood cancers—enjoy bipartisan support. What’s more, U.S. cancer researchers rely on the free flow of information facilitated by the WHO. Consequently, if Trump withdraws the United States from the WHO, U.S. cancer scientists could miss out on valuable resources, including those related to palliative care and pain management.

The NCCN letter in support of the WHO was signed by the American Association of Cancer Research, the American Cancer Society Cancer Action Network, the American Society of Hematology, the American Society for Radiation Oncology, the Association for Clinical Oncology, the Association of Pediatric Hematology/Oncology Nurses, CancerCare and the Hematology/Oncology Pharmacy Association.

AVAC, Health GAP and Treatment Action Group—global organizations working to prevent HIV and end AIDS—released their own joint statement denouncing Trump’s planned U.S. exit from WHO, stating that the move “will cost more lives and deepen economic devastation in the United States and around the world.”

“[Coronavirus] respects no borders; COVID-19 anywhere can quickly become COVID-19 everywhere. Global health emergencies require global leadership, and that requires a strong and supported World Health Organization,” said Mitchell Warren, AVAC’s executive director, in the statement. “The [Trump administration] is playing politics with people’s lives here in the U.S. and around the world. We will be left behind as the world comes together to collaborate and coordinate science as the best strategy to counter the pandemic, and we will lose ground in our historical investments to end HIV, [tuberculosis, TB], hepatitis C and other health issues.”

“We are seeing the disastrous effects of the U.S. federal government’s lack of strategy playing out every day in increased COVID cases and deaths of Americans, particularly in the Black community,” added Suraj Madoori, TAG’s U.S. and global health policy director. “Withdrawal from WHO will only compound the issues for our nation and for the world by further retreating on shared responsibilities in public health governance.”

In its own announcement, AIDS Healthcare Foundation (AHF), a nonprofit that operates HIV clinics nationwide and across the globe, also criticized the White House for plans to withdraw U.S. membership and funding from the WHO.

AHF acknowledged that the WHO made mistakes in handling the COVID-19 pandemic, notably in its dealings with China. (This topic is the impetus for Trump’s desire to pull the U.S. out of the organization after 72 years. He announced the plan to the public May 29 but only recently formally notified the United Nations; the U.S. withdrawal won’t take place until next summer, though presidential hopeful Joe Biden said that if he’s elected, the United States will remain in the WHO.)

“The fact that the World Health Organization’s response to COVID-19 has fallen far short and that it aided China in covering up its own timeline and response to the pandemic does not justify pulling the United States out of the only international body working today to address global health issues like the deadly coronavirus,” said Michael Weinstein, president of AHF, in a statement from May 29. “We are in the middle of a worldwide pandemic.… The Trump administration’s action today reflects very poorly on the U.S. and will be catastrophic for global public health for years to come.”

Editor’s note: This article was updated to correctly name the organization Treatment Action Group.