Editor's note: This story was updated on April 8 to reflect new data released by the World Health Organization.

The ongoing war in Ukraine has affected 18 million people, with more than 4 million having fled the country. The World Health Organization (WHO) announced Wednesday that more than 100 attacks on health care had been verified since the start of the war, accounting for 73 deaths and 51 injuries.

The impact on health care — the infrastructure, the workers, and the patients — is profound. Just as the world was starting to recover from the consequences of the COVID-19 pandemic, another crisis erupted, displacing and endangering the health and well-being of thousands of people. 

From medical supplies shortages and limited access to health care, to increased risk of infection, injuries, and death, the conflict in Ukraine has put people in urgent need of assistance across the country. If past conflicts have taught us anything about the impact of war on health care, it is that this situation is likely to worsen the longer the war continues.

Here are five ways war impacts global health and what you can do to help.

1. Access to Health Care Is Limited

When war erupts, hospitals and other facilities are often targeted or forced to shift their services to address the immediate crisis, all while running low on supplies. This results in decreased access to health care, particularly in already under-served or under-resourced areas with fragile health infrastructure. 

What's more, because health care workers are often targeted in conflicts, patients with chronic conditions — including asthma and diabetes — are forced to wait for extended periods for care. This can result in missed diagnoses and untreated conditions.

The conflict that broke out in 2020 in the Ethiopian region of Tigray, for instance, caused the health care system to collapse entirely. Six months into the war, only 27.5% of hospitals, 17.5% of health centers, and 11% of ambulances were fully operational, according to a recent study. 

Similarly, in Ukraine, facilities are running out of supplies at an alarming rate. At Chernihiv children’s hospital, where patients receive treatment for cancer, the Russian military presence in surrounding areas has caused the facility's food and medicine supply channels to be cut off.

2. Population Displacement Makes People More Vulnerable to Infectious Diseases

War forces people to flee, creating massive internal and cross-border population movement. Civilians often have to endure long journeys from one place to another, living in cramped refugee camps in poor sanitary conditions. In Ukraine alone, 6.5 million people have been displaced internally while another 3.2 million have fled to neighboring countries.

Contrary to popular belief, population movement itself isn't associated with the spread of illness, rather, it is the vulnerability of displaced people that makes them more susceptible to contracting communicable diseases such as HIV/AIDS and TB. 

“Anytime you disrupt society like this and put literally millions of people on the move, infectious disease will exploit that,” US Chief Medical Advisor Anthony Fauci told the Telegraph. “People are packed together, they’re stressed, they’re not eating, not sleeping properly. They’re highly susceptible [to disease].”

3. Mental Health Is Likely to Deteriorate

Aside from their severe effects on physical health, conflicts take an enormous toll on mental health. Prolonged exposure to trauma, loss of life, disruption of normal social and work lives, and uncertainty over the future are all factors that lead to severe mental and emotional stress. 

Globally, data from the WHO suggests that mental illness is prevalent among populations affected by conflict — 1 in 5 people experiencing conflict face mental illness. 

In Gaza, for instance, Doctors Without Borders found that 40% of young people suffer from mood disorders, 60% to 70% from post-traumatic stress disorder (PTSD), and 90% from other stress-related conditions.

4.  Access to Food and Water Is Limited 

In times of crisis, access to water, sanitation, and hygiene (WASH) and adequate nutrition is almost always compromised. Water sources are often contaminated, and water treatment systems frequently damaged, creating a breeding ground for water-borne illnesses, such as cholera and diarrhea. 

According to UNICEF, people in conflict-affected areas are three times as likely to practice open defecation, four times as likely to lack basic sanitation services, and eight times as likely to lack basic drinking water. The risk is particularly high among children under 5 as they are more likely to die due to WASH-related illness than any other age group. 

Food shortages are also common. While starvation as a warfare method is prohibited under the Geneva Convention, military activity results in disruptions to food production and supply chains, leading to skyrocketing prices and higher risks of acute malnutrition. In 2020 alone, food costs had soared up to 50% in Ethiopia and Yemen, putting millions of people on the brink of starvation.

5. Routine Immunization Programs Are Disrupted

Routine immunization programs are often brought to a standstill during conflicts, leaving populations susceptible to epidemics and disease outbreaks that could otherwise have been prevented.

This is especially crucial when you consider COVID-19 or polio, which currently has no cure. With consequences ranging from lifelong paralysis to death, the latter is particularly threatening to children under 5 — and getting vaccinated is the best way to prevent it. 

In Ukraine, polio vaccine uptake was already lagging before the war began. In 2014, a mere 50% of Ukrainian children were fully immunized against polio and other preventable diseases, according to the WHO. The conflict is likely to make the situation worse.

After one polio case was identified in the Rivne region in October 2021, the government unveiled a program to stop the outbreak in its tracks. But Russia’s invasion brought its implementation to a halt, with supply shortages, dysfunctional hospitals, and displacement creating additional hardships for communities.

What Can Global Citizens Do?

From Kyiv to Kabul, conflicts have destructive consequences on people's health and livelihoods — that's why Global Citizen is calling on world leaders and the corporate sector to do their part. Tomorrow, join us for the largest global digital rally to #StandUpForUkraine and refugees around the world.