In the COVID fall of 2020, my elderly mother came to live with us in Maine.

The metallic hardware in her knee was infected, and she needed IV antibiotics for weeks. She was one of the lucky patients. First, I have been a nursing home doctor in Lewiston for nearly 15 years. Second, by living with us she avoided the profound isolation others suffered during this time.

During COVID, frail elderly people did not have visitors for months. Humans lived and died without the warmth of touch or the presence of family. As an Army physician who served in Iraq in 2007, I learned the harsh necessity of triage — making life-and-death decisions when resources are limited. In 2020, alongside my dedicated colleagues in Lewiston, we faced a similar reality when combating the novel infectious disease. My mom survived her infection and a bout with COVID; many Mainers, young and old, did not.

As a geriatrician for hundreds of residents in central Maine, I am deeply concerned about how new outbreaks of disease — such as measles and bird flu — may soon affect our state. Unfortunately, Maine’s communities are at greater risk to communicable infections because of the Trump administration’s decision to withdraw the United States from the World Health Organization (WHO).

While many Americans think of the WHO as a global organization that conducts life-saving work to eradicate disease and vaccinate people abroad, they overlook WHO’s impact here. The WHO is the world’s early warning system for emerging public health threats, helping to stop outbreaks from becoming full-blown pandemics by coordinating a global response and sharing vital information. Global health is community health.

Maine’s population is among the oldest in the country, with nearly one in four residents over the age of 60. That means Mainers — particularly older adults or those with chronic conditions — are uniquely susceptible to public health threats.

When it comes to public health, early detection and action is critical. Diseases do not respect borders, and a crisis anywhere can quickly become a crisis everywhere. For instance, an individual who contracts influenza in one of the nursing homes I service inevitably affects the entire nursing home community via resource management, caregiver burnout and direct threat of the disease process itself.

Exiting the WHO will isolate the U.S. off from vital collaboration. As a result, we are less prepared to fight outbreaks like measles, drug-resistant tuberculosis and bird flu, which has recently started spreading to dairy herds and sheep. (Maine’s Department of Agriculture recently upgraded the risk of bird flu spread from “Moderate” to “High.”)

The WHO plays a crucial role in advancing research that benefits Maine residents, particularly in addressing diseases like dementia and Alzheimer’s. As a doctor, I rely on global research to provide the best care, and losing this resource would negatively affect outcomes for the 30,000 Mainers aged 65 and older living with Alzheimer’s.

During my deployment to Iraq, I saw firsthand how health and global security go hand in hand. The WHO is not just a public health organization — it is a key diplomatic and peacekeeping tool. Investing in global health and providing medical training around the world strengthens relationships, reduces conflict and ultimately makes the world and Maine healthier and safer.

The WHO strengthens our communities, protects our seniors and safeguards us from public health threats. Leaving the WHO will have serious consequences for our state and our people. I urge our elected officials — including U.S. Sens. Susan Collins and Angus King, as well as U.S. Rep. Jared Golden — to call on the Trump administration to rejoin the WHO and to continue funding this critical work.

We cannot afford to walk away.