Dr. Yvonne "Bonnie" Maldonado was in a San Francisco hotel room preparing to go out for a New Year's Eve dinner with her husband, when she saw a television news story about an ongoing outbreak of severe pneumonia in China.

The infectious disease specialist had first heard about the pneumonia outbreak in November 2019. But at that moment, she said, it became clear to her that something more was happening.

The familiar worries she'd felt about the SARS outbreak in 2002 resurfaced. But SARS fizzled out, and this new outbreak was picking up speed.

"I thought, 'Oh my gosh, it hasn't gone away yet. So it's going to be important," said Maldonado, professor of pediatric infectious diseases and health research and policy at Stanford University. "I made a mental note to myself: I need to check in at the hospital tomorrow, or after New Year's, and make sure that we're screening our patients. ... I made a mental note to myself to check in with my team the next day and make sure we were tracking travelers with fevers, especially those who came into the hospital."

Maldonado had the students in her epidemiology of infectious diseases class start tracking cases of the virus through websites.

"I didn't know where it would be headed, but I wanted to teach students that this is how you track diseases and how you can check it off and say it's not a problem, or yes, it needs to be continued to be followed. ... We started realizing that this was not going to be a trivial problem."

Maldonado has since made significant contributions in the study of SARS-CoV-2, which causes COVID-19. Among her work are studies of nasal swab techniques that led to home testing and the development of an antibody test to detect the virus, which received Food and Drug Administration approval. Because of her work, Stanford also is recognized for developing its own PCR tests before any other private institution in the U.S.

On Thursday, April 21, Maldonado will receive the Tall Tree Global Impact Award from the Palo Alto Chamber of Commerce and the Palo Alto Weekly for her unparalleled frontline work during the coronavirus pandemic. This is only the third time since the launch of the awards program in 1980 that Tall Trees has given out a Global Impact Award recognizing a community member whose work has had a long, significant influence beyond Palo Alto.

"My job here is to keep my hospital safe and our patients safe. And that was the first thing I started to think about," Maldonado said.

Having worked in global health in the midst of cholera outbreaks and in countries where there was Ebola virus, she began to prepare for the SARS-CoV-2 virus to spread. Well before community transmission became commonplace, she began to think about how to prepare for an influx of cases: Are we ready for cases when they come? What do we do? How do we treat isolation and containment policies?

"When it became clear that there was community transmission, that's when I said, 'OK, now we have to pull the trigger because it's here,'" she recalled.

And that happened rapidly, she said. By March or April 2020, Stanford already had testing tents outside and were testing people.

"At one point I think we were testing 30% of all the people in California because there were some problems with the CDC PCR tests, and we had our own tests that the FDA had reviewed and validated for us," she said.

Maldonado came from humble beginnings. Her parents, Mexican immigrants who moved to Los Angeles, sought the typical American Dream, working their way up from the bottom, and they just wanted their children to go to college, she said.

"My sister and I had to figure out how to get there, with their support, obviously, but what decisions needed to be made were really made by us without a lot of input because we didn't have anyone who could advise us. ... So I had to go with what I was interested in. And I was always very interested in science," she recalled.

Maldonado received her medical degree from Stanford University School of Medicine and performed her residency in pediatrics and a fellowship in pediatric infectious diseases at Johns Hopkins Hospital. She became a U.S. Centers for Disease Control and Prevention epidemic intelligence service officer at the beginning of the HIV/AIDS outbreak in the U.S. in the 1980s. She has worked in Zimbabwe to reduce perinatal HIV transmission from pregnant women to their infants and on vaccine development and distribution in developing countries, including in Mexico. She is the founder of Stanford's pediatric HIV Clinic.

"I really liked this idea of social justice. I guess we didn't call it that then, but my parents were always working in the community. Here in the U.S., and even back home, we were always volunteering and helping people who are less fortunate. So there was always a sense of giving back and community," she said. "Especially because I went into infectious diseases and working with vaccines, in particular, and children, it was very hard to ignore the fact that in so many parts of the world children were dying of diseases that we wouldn't think of having in developed countries, or they were just either present or in very low numbers or children didn't die from some of these diseases.

"So this idea of reaching out across not just U.S. but international boundaries and lesser-resource countries was really fascinating to me. I just thought that was where you could make the most impact and in the most rapid way possible," she said.

She said SARS-CoV-2 has been singularly surprising.

"I think one of the things — there were many things that surprised me, obviously — but the way this virus manifested itself was so unusual. Some people were asymptomatic. Some people had mild symptoms. Other people had intense inflammatory system symptoms and other people had purely respiratory manifestations, and just this whole gamut. It was really difficult to understand.

"The other thing that I think was surprising over time is how these viruses were able to mutate and really dominate. They were able to dominate whole countries and all regions of the world. That was also interesting," she said.

Looking into the future, Maldonado said: "We just don't know what to expect. What will happen with the next set of mutations? Will they be worse? Better? the same?

"It's been two years. I'm just constantly adapting to this virus as it adapts to us," she said.

Read more stories on the 2020 and 2022 Tall Tree Award honorees:

• Dr. Sara Cody: Making the tough decisions

• Cammie Vail: Paying it forward

• Pastor Paul Bains: 'Hope' for the unhoused

• Hal Mickelson: Steering the future of Palo Alto's past

• Roger Smith: Finding justice for murder victims' families

• Palo Alto Players: The art of lifting a community's spirit

• Peninsula Open Space Trust: Committed to conservation

• Premier Properties: Taking care of businesses

• Homewood Suites: Opening it doors to nonprofits, people in need