The coronavirus is raging through the White Mountain Apache tribe. Spread across a large reservation in eastern Arizona, the Apaches have been infected at more than 10 times the rate of people in the state as a whole.

Yet their death rate from COVID-19 is far lower, just 1.3%, as compared with 2.1% in Arizona. Epidemiologists have a hopeful theory about what led to this startling result: Intensive contact tracing on the reservation likely enabled teams that included doctors to find and treat gravely ill people before it was too late to save them.

A crucial tool has been a simple, inexpensive medical device: an oximeter that, clipped to a finger, detected dangerously low blood oxygen levels in people who often didn’t even realize they were seriously ill.

Contact tracing is generally used to identify and isolate the infected, and to slow the spread of the coronavirus. Elsewhere in the United States, the strategy mostly is failing; the virus has spread too widely, and tracers are struggling to keep up.

But on the reservation, contact tracers have discovered effective new tactics as they trek from home to faraway home. They may not have been able to stop the virus, but they have managed to prevent it from causing so many deaths.

“This is really not about contact tracing cutting down spread,” said Dr. Arnold Monto, a professor of epidemiology and public health at the University of Michigan who was not involved in the project but reviewed the findings. “Do it right, and the mortality will be lower.”

“This could help with other hard-to-reach communities,” he added. “If we identify cases sooner, they won’t come in half dead with horrible lungs.”

This approach, which doctors at the Indian Health Service laid out recently in the New England Journal of Medicine, may offer a new strategy for reducing COVID-19 deaths in some of the hardest-hit communities, Monto and other experts suggested — especially among people of color who more often live in housing where multiple generations share space.

Dr. Vincent Marconi, director of infectious diseases research at Emory University in Atlanta, said it was “incredible” that contact tracing could have such an effect on a population so disadvantaged and at such high risk.

If the reservation’s methods have lowered death rates, he added, “then absolutely, without a doubt, this needs to be replicated elsewhere.”

A Walk in the Yard

When the virus came to the Fort Apache reservation in April, doctors at the Indian Health Service were prepared to deploy contact-tracing teams to track the spread of the virus — and try to stop it.

“We were ready when it hit us,” said Dr. James McAuley, clinical director of the Whiteriver Indian Hospital, which serves the Apache community.

The reservation’s contact-tracing team includes 30 members. The day starts with a meeting at 8 a.m., in which each newly diagnosed case is assigned to a contact tracer and staff members review what they have learned about the people they are following.

Dr. Ryan Close, an Indian Health Service physician, writes the names of patients and contacts on four large whiteboards. Then the contact tracers — garbed in masks, gloves and gowns — set off in small teams to visit homes.

Each team includes a doctor and, when possible, community members like Grant Real Bird, a senior at Arizona State University who speaks the Apache language. His grandfather is well known to tribe members.

Many who are infected with the virus live in multifamily dwellings where isolation is impossible. Not only are members of the household exposed, but people with the virus often have also been out in the community for days with vague symptoms they did not realize signaled the start of an infection.

When the doctors started visiting the homes of infected people, many of whom were at high risk of complications because of underlying conditions like diabetes or obesity, they focused on testing their blood oxygen levels.

The coronavirus can impair the lungs in quiet, almost unnoticeable ways. People may not be gasping for breath, one of the classic signs of low oxygen levels, but the contact tracers often found their levels were perilously low. Without supplemental oxygen, these people risked permanent organ damage and death.

That led to a new strategy, Close said: “Contact tracing is a moderate end in itself, but the primary objective is to identify the high-risk individual” — those in grave danger from lack of oxygen. The team visits patients risking serious illness every day, and the moment their blood oxygen levels drop, they are taken to the hospital for oxygen therapy.

At the same time, the teams made another discovery. In the homes of coronavirus patients, the contact tracers noticed family members who did not look healthy. Often the signs were subtle, but the doctors, who know so many of the residents, recognized changes in complexion or energy levels.

The doctors asked family members who looked ill to take a brief walk around the room, or into the yard and back, with an oxygen monitor clipped to their fingers. Over and over, they saw the same thing — people who had oxygen levels so low they should be gasping for air. Yet they showed none of the expected symptoms.

“It’s a fairly common scenario,” said Dr. Dominick Maggio, director of the emergency department at Whiteriver Indian Hospital. “The team goes out looking for one person and finds someone else.”

Final Goodbyes

Some researchers are now convinced that an expanded

mandate for contact tracing, not genetics or some other hidden factor, explains the lower death rates on the reservation compared with the state.

Like other groups living in crowded conditions, the Apaches would be expected to have an alarmingly high death rate, Monto said.

“The higher impact in minority populations is not based on increased susceptibility of these populations, but rather higher infection rates and poorer outcomes based on late detection and underlying conditions,” he said.

Few dispute that identifying patients heading into serious trouble has a powerful human benefit: It may give family members a chance to say goodbye.

On a recent Saturday morning, Maggio visited the home of his fourth patient that day, looking for a woman who was supposed to have been discharged from the hospital but who was not home yet.

Adults were cooking breakfast, children were watching television. And in the back bedroom, Timothy Clawson Sr., 93, was lying in bed, feeling tired but not especially ill.

“I was chatting with him and put a pulse oximeter on his hand,” Maggio said. “It started blaring.” Clawson’s blood oxygen level was 65%, dangerously low.

Ordinarily, someone with such a low oxygen level would look as if he or she is dying, Maggio said: “They would be pale, breathing fast, leaning forward putting their hands on their knees, trying to get air.”

But Clawson had no idea he was so sick. The family persuaded him to go to the hospital. He survived for just a few days.

His death was peaceful, said his granddaughter, Tamara Ivins. When she and her aunt visited, “We reached out and held his hand,” Ivins said.

“He told me: ‘This is it. I am going to see Grandma. Be strong for me.’”

“I told him, ‘Grandpa, I am going to pray for you.’”

Clawson’s large family gathered outside the hospital and said goodbye on FaceTime.

Ivins approached the contact tracers afterward and told them how grateful she was for the time to be with her grandfather at the end.

“It was a formative moment for me,” Close said. “You can’t save everybody, but there is still a tremendous value in giving people time.”

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