“Transforming Spaces” is a series about women driving change in sometimes unexpected places.

Kizzmekia Corbett had gone home to North Carolina for the holidays in 2019 when the headlines began to trickle in: A strange, pneumonialike illness was making dozens of people sick in China.

By the first week of January 2020, the number of infected people in China had climbed to the hundreds, and Dr. Corbett, a viral immunologist, was back at her desk at the National Institutes of Health, where she served as a senior research fellow at the Vaccine Research Center at the National Institute of Allergy and Infectious Diseases. And that’s when the news was confirmed: The mysterious illness was a novel coronavirus, exactly the category of infection that she had been probing for the past five years in a bid to develop a vaccine.

Coronaviruses can cause all kinds of illness, like the common cold or more crippling diseases like MERS and SARS. Novel coronaviruses are new strains that are identified in humans for the first time. And when it came to the race for a vaccine against Covid-19, Dr. Corbett, who was part of important work on other coronavirus outbreaks, was at the vanguard.

Next month will be the three-year anniversary of the World Health Organization’s declaring Covid-19 a pandemic, on March 11, 2020. But in those fraught first few months of 2020, Dr. Corbett helped lead a team of scientists that contributed to one of the most stunning achievements in the history of immunizations: a highly effective, easily manufactured vaccine against Covid-19, delivered and authorized for use in under a year.

On Jan. 6, 2020, that goal started to take on a new urgency. As the number of sick people in China began to climb, Dr. Corbett huddled with her supervisor, Dr. Barney Graham, the deputy director of the Vaccine Research Center and chief of the Viral Pathogenesis Laboratory. Both noted that this new disease bore eerie similarities to SARS and MERS, which each killed hundreds. Dr. Corbett’s work, and the work of her entire team, suddenly had urgent implications.

“At the time, we had no idea it would become a global pandemic,” she said. “So what I felt was excitement about being able to prove myself and my work to the world.”

Dr. Corbett, 37, was used to having to prove herself. As a Black woman in science, she is accustomed to asserting her worth in rooms filled with white men. In early 2020, she had been at the National Institutes of Health for five years, and had already published groundbreaking research about the structure of other coronaviruses, and how the viruses’ spike proteins — which form a distinctive crown shape on the surface of the virus and latch on to healthy cells in the body — act as the doorway to infection. This research was part of the foundation, laid by scientists including Dr. Graham, Katalin Kariko and Dr. Drew Weissman at the University of Pennsylvania, for the Covid-19 vaccine, the fastest vaccine ever developed.

Vaccines can take more than a decade to develop from scratch. The mumps vaccine, which was created in 1967 after four years, was considered a wild success of timing. By Jan. 10, 2020, at the urging of scientists including Dr. Graham, scientists in China shared the genetic makeup of the virus that was sweeping through Wuhan. He and Dr. Corbett immediately saw that their research on other illnesses caused by coronaviruses like SARS and MARS could be adapted relatively simply.

“Over the course of five years,” Dr. Corbett said, “we had already determined which parts of the virus would excite the body’s immune system in a way that would cause protective immunity.”

Understanding that spike proteins were at the heart of an adequate defense against infection, Dr. Corbett and other scientists had created experimental vaccines against SARS and MERS. Now, by swapping in the genetic code for the virus that creates Covid-19 — so named by the World Health Organization because it emerged in 2019 — they had a prototype they could already use. Dr. Corbett has referred to this ability to apply a template as the “plug and play” approach.

Dr. Graham credits her with playing a formative role in the vaccine’s development. “Around 2015, Kizzmekia decided that the coronavirus was the project she wanted to focus on,” he said, “and it was her work that led to what we knew about the coronavirus, and prepared us for making that vaccine so rapidly.”

It took her only a few hours to prepare a modified sequence for a vaccine. By Jan. 14, the N.I.H. had shared that sequence with the vaccine developer Moderna, which used the code to create synthetic messenger RNA, the genetic material that holds instructions for how to build the spike proteins, which are recognized by the body’s immune system and teach it how to fight the virus. Messenger RNA is the backbone of Moderna’s Covid-19 vaccine, and Pfizer’s vaccine, which also uses synthetic mRNA.

By March 2020, Moderna was running the first human trials of its vaccine, and by December 2020 — less than a year after the first deaths in Wuhan were reported — it was authorized by the Food and Drug Administration for emergency use.

Thinking back on those intensely charged first days, Dr. Corbett, now at Harvard, said, “we weren’t racing against the pandemic.”

“We were racing ourselves,” she continued. “It was all about proof of principle.” Initially, she was eager to prove that her earlier research could be widely applied. “But when hundreds of thousands of people start to die,” she said, “you realize how important the work you’re doing is.”

She also felt pressure beyond the rapidly climbing death toll. Dr. Corbett, who has a sharp sense of humor and an easygoing style, grew up in Hillsborough, N.C., and earned her Ph.D. in microbiology and immunology from the University of North Carolina at Chapel Hill in 2014. She is still working to upend the status quo when it comes to who performs scientific research.

“I try to make sure that my lab and the people I hire come from diverse backgrounds so that our thoughts and the way that we do our science shakes the table a little bit,” she said.

She first came on the radar of many Americans on March 3, 2020, when photos circulated of her standing in the N.I.H. laboratory, in a crisp white lab coat, amid a crowd of influential white men: President Donald J. Trump; Dr. Anthony Fauci; Dr. Graham; John Mascola, director of the Vaccine Research Center; and Alex Azar, then the secretary of the Department of Health and Human Services.

But just out of the frame, two other young Black women scientists — Cynthia Ziwawo and Olubukola Abiona, both researchers on Dr. Corbett’s team — were watching their leader carefully.

“I had never seen a Black woman scientist before working with Dr. Corbett,” said Ms. Ziwawo, 25, who is now in medical school at Indiana University. “It definitely impacted how I view minorities in science, especially those running the room.”

Ms. Abiona, 27, who is now in a dual M.D./Ph.D. program at Case Western Reserve University in Cleveland, also said she continued to emulate Dr. Corbett as she pursued her own training.

“Seeing Kizzmekia in a leadership role expanded how I see myself, and how I move through this space,” she said. “I use her as a role model.”

Dr. Corbett said she understood that in her work, she was still held accountable not just for herself, but also for hundreds of other scientists who look like her.

“There are people who I have out-published and out-successed, who are 60 years old and who have the nerve to ask me what I’m going to do next and what’s my expertise,” she said. “And I’m like, ‘You took my vaccine.’”

In May 2021, Dr. Corbett joined the faculty at Harvard’s T.H. Chan School of Public Health, where she is now an assistant professor in the Department of Immunology and Infectious Diseases. But she still carries the same kind of pressure she felt racing the clock in early 2020.

“If I fail as a Black woman, this department at Harvard will overlook Black women until infinity,” she said. “People at the N.I.H. would have overlooked Black women if I failed. Being the first in so many kinds of these spaces has so much pressure.”

She receives 10 to 20 emails a week from Black women and girls, she said, and whenever she talks to them, she makes a point to let them know that if they, too, want to be a scientist, “I will risk my all to make sure to stand up for them, as long as they are committed.”

“Women need people to stand up for them,” she continued. “Especially Black women.”

And in visits with Black churches, at community forums and on her active Twitter page, where she has more than 160,000 followers, she is vocal about combating vaccine hesitancy and decreasing barriers to health care, particularly among communities of color.

Playing a pivotal role in the creation of a Covid-19 vaccine, she admits, is her own hard act to follow. So now she is also focused on paving a path to help other Black women scientists shatter boundaries.

“At some point, you get to the point where you can’t beat what you already did,” she said. “But then you get to have a voice in spaces that you generally wouldn’t be able to. That’s where my mission and purpose is.”