On a GoFundMe page created in August, her sister Maureen explained that while Adeline usually worked delivering babies, on July 8 "she was doing a rotation in the ER, treating COVID patients."
"That morning she went into work feeling well and excited to see patients, but by the evening she began to feel under the weather. What started as intense flu-like symptoms escalated within the week to a hospital stay," Maureen wrote.
Adeline Fagan battled COVID-19 for weeks, her sister wrote. She was treated with several respiratory therapies and put on "dozens of drugs," but the treatments did not yield a positive response, so she joined an experimental drug trial. "However, before we could see if this new drug was effective, her lungs could no longer support her," her sister said.
Fagan was intubated in August and then put on an ECMO heart-lung machine to add oxygen to her blood— a form of life support, Maureen wrote.
Since Fagan's family is from Syracuse, New York, her parents had to travel between their home and Texas to see her. The GoFundMe page was created to help cover medical and travel expenses.
Last month, Adeline's sisters spoke to CBS Central New York affiliate WSTM and said they hoped her story would serve as a wake-up call and that people would take the threat of the virus seriously.
"Wear your mask, social distance, stay home if you can," Maureen Fagan said. "Do you part so that your daughter, your friend, your sister is not Adeline because this is absolutely terrible and I wouldn't wish this on anyone."
"Unfortunately Adeline's story could be their story. And that by following the rules, wearing a mask, social distancing, staying home if you can, you can help the situation and that is almost your duty to do," her sister Natalie added.
On September 19, Adeline's father, Brant Fagan, wrote a heartbreaking update on the GoFundMe page. "4:24 AM Central Time. The time the world stopped for a moment and will never be the same," he wrote. "Our beautiful daughter, sister, friend, physician, Adeline Marie Fagan, MD passed away."
He said she had been "doing wonderfully for the last few days," but on Saturday they got a call from her doctors in Houston. "There was a problem and we needed to decide about performing a procedure to relieve the pressure of a massive brain bleed," he wrote. "The nurse came into her room for a routine task and noticed Adeline was not responsive. They immediately rushed her for a CT scan which showed the extent of the damage."
"Everyone was crushed by the events, the nurses, the doctors, and, of course, us," Brant Fagan wrote. "The doctor said they have seen this type of event in COVID patients that spend time on ECMO. The vascular system is also compromised by the virus, resulting in bleeds. We spent the remaining minutes hugging, comforting, and talking to Adeline. And then the world stopped..."
Fagan's father thanked everyone who supported his daughter and their family during this time.
It is unclear if Fagan had any underlying conditions. While coronavirus disproportionately affects the elderly or people with medical conditions,and many have . CBS News has reached out to the Fagan family for more information.
Her death came as the nation approached a tragic milestone:since the pandemic began.
In remembering his daughter, Brant Fagan said if you can be one thing, be an Adeline — "passionate about helping others less fortunate, have a smile on your face, a laugh in your heart, and a Disney tune on your lips."