By Nicquel Terry Ellis, CNN

(CNN) -- They have administered Covid-19 vaccines on college campuses, provided testing at churches and spent long hours in labs developing an effective vaccine.

Some have given up their regular jobs and personal free time to do this work.

Black women have been at the helm of the nation's fight against the pandemic since the coronavirus hit US soil a little over one year ago.

For many of them, it's personal. Black women doctors and health advocates tell CNN they feel obligated to step up as people from their own communities face higher death and hospitalization rates.

They are also determined to use their platforms and credibility to combat vaccine hesitancy and prevent further devastation among Black and brown people.

Here are the stories of six Black women who are on the frontlines of the ongoing battle against Covid-19.

She went into Black neighborhoods of Philadelphia and began testing people

Dr. Ala Stanford, founder of the Black Doctors Covid-19 Consortium

Dr. Ala Stanford was at home quarantining with her family in Philadelphia last spring when she started getting phone calls from friends who were sick but couldn't get a Covid-19 test. Many were being rejected from testing sites because they didn't have referrals from their primary care doctors, or they didn't have cars and were walking up to drive-thru locations.

Stanford, a pediatric surgeon, said she immediately became concerned, especially with new data showing Black people were dying from Covid-19 at higher rates than White people.

So she sprung into action.

Stanford called up friends who were doctors and medical students, gathered all of the masks and gloves she had, ordered testing kits, rented a van and went out into Black neighborhoods and started testing people.

In the following weeks, Stanford's operation would grow and she officially established the Black Doctors Covid-19 Consortium. The organization began partnering with churches and setting up mobile testing sites at parks to ensure Philadelphia's Black community had access to tests.

"I wanted us to be the Black Doctors Covid-19 Consortium on purpose so that people knew that we as Black healthcare professionals care about your life," Stanford said in an interview with CNN. "And even though no one else is getting a test to you or coming to your neighborhood, we are coming to your neighborhood."

The group recently began offering Covid-19 vaccines in hard-hit areas of Philadelphia. Stanford said her mission is to help people of color who are elderly, vulnerable or have no other options for getting the vaccine.

So far Stanford said the Black Doctors Covid-19 Consortium has tested more than 24,000 people and vaccinated more than 16,000. The organization hosted a 24-hour "Vaxathon" event last month during which it administered the shot to nearly 4,000 people, surpassing Philadelphia's daily vaccination average of 3,500 doses per day.

Stanford, who tested positive herself for Covid-19 antibodies last October, said she feels encouraged by the influx of Black people who have been signing up to get the vaccine from her organization.

However, she believes many Black Americans remain hesitant to get the shot due to a lack of information and fear of long-term health impacts.

Stanford said she tells people the risk of getting Covid-19 outweighs the risk of taking the vaccine.

"Some things you're not going to have answers to," Stanford said. "But we can deal with the present right now and know that without it (the vaccine), more people will lose their lives, more people will be confined to the house, we will continue to have liberties that we want taken from us for our survival."

She helped develop Moderna's coronavirus vaccine

Dr. Kizzmekia Corbett, viral immunologist for the National Institute of Allergy and Infectious Diseases

Dr. Kizzmekia Corbett discovered her passion for science and solving problems at a young age.

She spent her childhood winning regional science fairs, mastering math equations and doing internships in the science field.

Corbett went on to the University of Maryland Baltimore County where she studied health disparities and took an interest in vaccine development.

Eventually, Corbett decided that figuring out the world's problems was her purpose in life.

Corbett, a viral immunologist for the National Institute of Allergy and Infectious Diseases, was one of the lead scientists behind the development of the Moderna Covid-19 vaccine.

"It became clear to me that for every single thing that I've read in a textbook about science, someone had to discover that," Corbett said in December on an episode of the CNN podcast "Coronavirus: Fact vs. Fiction." "And I wanted to be one of those people that for a line in a textbook, which hopefully mRNA-1273 [the Moderna vaccine] will be at some point, there's someone who discovered that thing and helped to drive that theory."

Last year, Dr. Anthony Fauci praised Corbett when he said she was among the Black scientists involved in developing the Covid-19 vaccine.

"So, the first thing you might want to say to my African American brothers and sisters is that the vaccine that you're going to be taking was developed by an African American woman," Fauci said. "And that is just a fact."

Corbett said her work around the spike protein and immune responses prepared her for the ambitious task of developing a Covid-19 vaccine in less than a year. Most vaccines take many years to develop and get federal approval.

Corbett told CNN last April that there would be an authorized vaccine available by the end of 2020 -- and she and her team delivered.

Corbett said she slept with the burden of the world on her shoulders, working daily to create a Covid-19 vaccine as the deadly virus quickly spread. Corbett said she cried when the efficacy results showed the vaccine worked.

"I felt like there was no room for mistakes, which was difficult because science -- mistakes are actually part of the beauty of it," Corbett said. "Not necessarily tons of mistakes, but you learn a lot from things that don't necessarily always go right with experiments. But in this case, we only had the bandwidth to learn from things that were going to go right. Otherwise, you lost time and people died."

Corbett has also spoken out about systemic racism during the pandemic. She criticized former President Donald Trump for the lack of diversity on his coronavirus taskforce.

Corbett acknowledged the data that shows many people of color don't trust the vaccine and don't plan on taking it. She said the onus is on scientists, physicians and vaccine developers to prove they are trustworthy.

"What I say to people, firstly, is that I empathize and then, secondly, is that I'm going to do my part in laying those bricks," Corbett said. "And I think that if everyone on our side, as physicians and scientists, went about it that way, then the trust would start to be rebuilt."

She is the face of President Biden's Covid-19 equity plan

Dr. Marcella Nunez-Smith, Chair of the Biden Administration's Covid-19 Health Equity Task Force

Dr. Marcella Nunez-Smith has dedicated her career to addressing health disparities in marginalized communities.

Nunez-Smith, a Yale professor of internal medicine, epidemiology and public health, has studied everything from racial discrimination in health care — an issue that has fueled vaccine distrust with people of color — to the disproportionate number of Black Americans who die from cancer.

So for those who know Nunez-Smith and have worked with her, it was no surprise when President Joe Biden tapped her to chair his Covid-19 Health Equity Task Force.

Since being appointed, Nunez-Smith has been the face of the Biden administration's plan to address health inequities, create equal access to the Covid-19 vaccine and build trust in communities of color.

Nunez-Smith, who previously served as co-chair of Biden's Covid-19 Advisory Board, has appeared before Black pastors, civil rights leaders and onTV to discuss how the vaccine works, why it is safe and necessary, and the administration's plan for reaching vulnerable populations.

She touts Biden's five-point plan which includes putting federally supported vaccination centers in high-risk neighborhoods, setting up mobile vaccination sites in medically underserved areas, administering the vaccine at independent pharmacies, partnering with community health centers and ensuring high-risk facilities such as jails and homeless shelters have access to the vaccine.

Nunez-Smith said it is critical to counter disinformation about the vaccine and maintains that the shot is effective on all racial groups. Earlier this year, Nunez-Smith announced that she had gotten the vaccine and experienced a sore arm which she said is "within the range of normal side effects."

"We all want to reclaim our joy to gather in person for worship and family," Nunez-Smith said during a virtual event hosted by Choose Healthy Life in January. "To send our children to school, to fully reopen our businesses, testing therapies and vaccines are the tools we have to get us there."

Debra Fraser-Howze, founder of Choose Health Life, said Nunez-Smith has been pivotal to the Black community's fight against Covid-19.

"Marcella Nunez-Smith is a gift," Fraser-Howze said. "She is everything we need at this moment."

Nunez-Smith has also advocated for expanded access to Covid-19 testing in Black communities, saying during the Choose Healthy Life event that "too many African Americans get their first test for Covid-19 when they're getting admitted to the hospital."

Outside of Biden's team, Nunez-Smith has established herself as a leading advocate for health equity at Yale. She is the founding director of the Equity Research and Innovation Center (ERIC) and leads the Center for Community Engagement and Health Equity (CEHE) within the Yale Cancer Center.

An article published by the ERIC said Nunez-Smith experienced health inequity firsthand when her father had a stroke in his 40s and was left paralyzed.

"I learned there was a term for what we were: an underserved community, marginalized by place and by race," she said, according to the article.

Nunez-Smith is originally from the US Virgin Islands and attended Jefferson Medical College. She has received dozens of awards and accolades for her work and has a love for mentoring.

"I could not have imagined any of this. It's not about me. It's never been about me," Nunez-Smith said. "This is about the work that needs to be done. I look into the eyes of my three young children and find courage to create something better for them moving forward."

These two Morehouse deans are vaccinating Atlanta residents

Dr. Valerie Montgomery Rice, President and Dean of Morehouse Medical School; Dr. Michelle Nichols, Associate Dean of Morehouse Medical School

When Morehouse Medical School Dean Dr. Valerie Montgomery Rice told Dr. Michelle Nichols she wanted to offer the Covid-19 vaccine at the school, Nichols was determined make it happen.

Nichols, who is an associate dean at the school, spent Christmas Eve and Christmas Day filling out paperwork to ensure Morehouse had all the certifications to become a vaccine provider.

Nichols and Rice then decided they would start with a small operation and expand. They hosted an event in early January where they vaccinated nearly 30 civil rights leaders.

Then they set up a parking deck on campus and administered the shot to about 150 local residents. They would double and triple that number in the following weeks while adding vaccination sites at Morehouse clinics. By the end of January, Morehouse had vaccinated 1,700 people.

Nichols said she and Rice are filling a void in the Black community.

"There are health disparities," Nichols said. "And there's always been the talk that some groups of people have greater access to vaccines than others."

Nichols, who is a family medicine doctor, said she has always been passionate about health equity and giving back to the community.

The Covid-19 pandemic gave her a new purpose -- vaccinating vulnerable populations, she said.

Nichols said Morehouse is well positioned to vaccinate people of color because the historically Black college has the community's trust.

Nichols and Rice have also led by example.

In December, Rice received the vaccine on CNN with Dr. Sanjay Gupta at Grady Memorial Hospital in Atlanta. Nichols received the shot later that month.

Rice said she understands that some Black Americans are hesitant to get the shot because of the nation's history of racism in medical research, but insists she wouldn't recommend a vaccine she didn't trust. Black scientists and doctors helped develop the vaccine and sat on the FDA and CDC advisory boards, Rice said during the event where she received the shot.

"We are in the rooms where it's happening," Rice said. "So we clearly are not going to go against ourselves. Because we understand how critical this is for Black America and Latinx America who have been disproportionately impacted by the virus."

Rice has also been at the helm of the school's efforts to recruit people of color for Novavax Covid-19 vaccine trials. Studies show that Black and Latino Americans are vastly underrepresented in US-based vaccine trials.

Nichols described Rice as an "excellent leader" and a "visionary" when it comes to the advancement of health equity.

"When she has her vision it's my job to make sure that it gets done," Nichols said.

She united Black clergy to fight the virus

Debra Fraser-Howze, founder of Choose Healthy Life

Debra Fraser-Howze was not surprised when data emerged last year showing Black people were dying from Covid-19 at higher rates.

She had spent her career lobbying for federal funds to fight AIDS in the Black community and helped develop rapid tests for Hepatitis C and Ebola.

And every virus had the same outcome: Black people were hit the hardest, she said.

"We have underlying health conditions that have never been addressed," Fraser-Howze said. "We survive barely in a medical system full of racism and disregard for us as a people."

In an effort to address the pandemic's devastating toll on the Black community, Fraser-Howze partnered with prominent Black pastors last spring to launch Choose Healthy Life.

The organization aims to provide awareness and education on Covid-19, and provide testing, vaccines and infrastructure to underserved Black communities.

Choose Health Life is co-chaired by the Rev. Al Sharpton and Rev. Calvin O. Butts III. Fraser-Howze said she handpicked the two pastors after working with them in the past on health equity issues.

The group's target cities include New York, Newark, Atlanta, Detroit and Washington.

Fraser-Howze said she wanted pastors at the helm of her effort because they are trusted leaders in their communities.

"They are the people that you go to in crisis," she said.

Since launching Choose Healthy Life, pastors have hosted Covid-19 testing events at their churches and are now working on plans to provide vaccines, Fraser-Howze said.

Choose Healthy Life also hosted a virtual awareness event with Black clergy and leading health officials, including Dr. Anthony Fauci and Dr. Marcella Nunez-Smith, in January to discuss the organization's mission. Sharpton and other Black clergy affiliated with Choose Healthy Life have gotten the vaccine at live events in recent weeks to combat vaccine hesitancy among Black Americans.

Fraser-Howze said she is committed to saving lives in the Black community through her work. She came out of retirement to create Choose Healthy Life.

Fraser-Howze had previously led the National Black Leadership Commission on AIDS (NBLCA) and held an executive role at OraSure Technologies where she helped create rapid tests for Ebola and Hepatitis C.

"It was almost as if God had prepared me — for all the things that I had done, for this moment," she said. "Looking at the death rate of the (Black) community, I think God realized that I could not just sit down, I had to get up."