As a critical care doctor in New York City, Monica is used to dealing with high-octane situations and treating severely ill patients. But she says the COVID-19 outbreak is unlike anything she’s seen before. Over the past few weeks, operating rooms have been transformed into ICUs, physicians of all backgrounds have been drafted into emergency room work, and two of her colleagues became ICU patients. While Monica is proud of her coworkers for rising to the challenge, she says it’s been hard for them to fight a prolonged battle against a deadly, highly contagious illness with no known cure.

To make matters worse, Monica recently tested positive for COVID-19, and she believes she brought the virus home to her husband. Both have gotten sick and are improving, but he had a much harder time with the disease than she did. Monica says that, while she’s used the inherent risk of her job, she feels her hospital failed to protect her and her family — and she blames herself, in part, for her husband’s illness. “There’s this sinking feeling that you have,” says Monica, who requested anonymity because she feared professional repercussions for speaking candidly, “not only, like, the hospital let you down, and that the system let us down as doctors and didn’t protect us, but then I didn’t protect my own family.”

In hospitals around the world, doctors, nurses and other healthcare workers like Monica are fighting an enemy that has already killed more than 95,000 people, including over 16,000 in the United States. And as with any war, the fight against COVID-19 will result not just in direct casualties, but also take a terrible toll on the minds of many of those who survive.

It will be years before the mental health toll of the COVID-19 pandemic is fully understood, but some early data already paints a bleak picture. A study published March 23 in the medical journal JAMA found that, among 1,257 healthcare workers working with COVID-19 patients in China, 50.4% reported symptoms of depression, 44.6% symptoms of anxiety, 34% insomnia, and 71.5% reported distress. Nurses and other frontline workers were among those with the most severe symptoms.

In interviews with TIME, several doctors and nurses said that fighting COVID-19 is making them feel more dedicated to their profession, and determined to push through and help their patients. However, many also admitted to harboring darker feelings. They’re afraid of spreading the disease to their families, frustrated about a lack of adequate protective gear and a sense they can’t do enough for their patients, exhausted as hours have stretched longer without a clear end in sight, and, most of all, deeply sad for their dying patients, many of whom are slipping away without their loved ones at their side.

It’s those lonely deaths that have hit the hardest for some. Natalie Jones, an ICU-registered nurse at Robert Wood Johnson University Hospital Hamilton in New Jersey, says it’s been agonizing to have to turn away people who want to visit their loved ones one last time. She’s trying to find ways to be compassionate where she can — last week, she passed on a message from a patient’s wife just before he died: “That they love him, and it’s O.K. to go.” But even simply carrying a message of such emotional weight can take a toll.

“We carry that burden for the families, too,” says Jones, who’s having difficultly sleeping without nightmares. “And we understand it’s so difficult that they can’t be there. And that hurts us too. As nurses, we’re healers, and we’re compassionate. It hits very close to home for us as well.”

“We’re all affected,” adds Jones, whose already hectic schedule has gotten even more intense amid the outbreak, costing her the sleep that might otherwise help her cope with what she’s experiencing. “To say that we’re not would be a lie.”

The coronavirus is taking a mental toll even on those medical experts who aren’t on the front lines. Since the start of the outbreak, Dr. Morgan Katz, an infectious disease expert at Johns Hopkins University, has been advising nursing homes and long-term care centers on dealing with the coronavirus. But she’s struggling with the gap between what she believes to be the proper procedures and what’s actually possible in this crisis. Many of the facilities she’s advising are suffering from a lack of protective equipment, limited staffing and insufficient testing, and a sense of helplessness is taking hold.

“We didn’t have the resources before this that we needed, and this has completely strapped them beyond anything feasible,” says Katz. “It’s so sad. I really feel for these nursing homes and the staff of these nursing homes, because I truly believe that they’re trying to do the right thing. But I really don’t feel like they’re being protected the way that we need to protect them.”

Finding ways to support medical workers’ mental health could be a key component in the fight against COVID-19. Dr. Albert Wu, professor of health policy and management and medicine at the Johns Hopkins Bloomberg School of Public Health, says that evidence from the 2003 SARS outbreak suggests that failing to support healthcare workers in a crisis, including by not providing enough protective gear, can erode their “wellbeing and resilience,” ultimately leading to chronic burnout. Some healthcare workers could leave the profession, be absent more often from work, or develop PTSD, and any preexisting mental health conditions could be exacerbated. Furthermore, healthcare workers are human like the rest of us, and under extreme stress, they could be prone to making mistakes — which could lead to worse outcomes for patients, and further erode doctors’ and nurses’ mental health. “We can’t get away from our physiology,” says Wu.

If healthcare workers can’t provide the care they typically believe is medically necessary for their patients, they may experience a phenomenon known as “moral injury,” says Dr. Wendy Dean, a psychiatrist and the co-founder of the nonprofit Fix Moral Injury. Dean says that American healthcare providers are used to doing anything and everything to help their patients, but inadequate protective gear and triage procedures will force them to make “exquisitely painful” decisions, such as choosing whether or not to risk infecting themselves, their family and other patients in order to help everyone in their care.

Still, Dean says the scope of the mental health crisis among healthcare workers won’t come into focus until the more immediate problem has ebbed.

“When I think the real challenge is going to come is when the pandemic eases up and people start having time to process,” she says. “All that they’ve seen, all that they’ve done, all that they’ve felt and pushed away.”

Several healthcare workers said that, amid all the uncertainty and horrors, they have found some relief in drawing upon support from their families, communities, and one another. Monica, for one, says her friends brought food to her and her husband after they got sick, and she deeply appreciated the support. She’s also proud of the way her colleagues have come together as a team to fight the virus. “There has been a real feeling of, everybody’s in the trenches together,” she says. “What I’ve been most amazed about is people have really risen to that call.”

Please send tips, leads, and stories from the frontlines to virus@time.com.

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