Maura Caldwell's hopes of getting her parents inoculated against the deadly coronavirus seemed to be slipping away as she watched hundreds of people — some in wheelchairs or walking with canes — rush toward the entrance of Children's Minnesota Hospital in south Minneapolis.

Like those in the surging crowd, Caldwell and her parents, both in their late 60s, had heard by word of mouth that extra doses of the Pfizer vaccine had suddenly become available at the hospital — and the doses would expire if they didn't get into people's arms that frigid January morning. No one knew how many shots were on hand as they climbed out of cars and buses, forming a line that snaked through the hospital's parking garage and around the block.

Caldwell's parents would endure nearly four hours of anxious waiting and confusion before they finally reached the front of the line and received the shots.

"It was like 'The Hunger Games,' " Caldwell said, referring to the post-apocalyptic film in which people fight one another to survive. "It really felt like it was every man and woman for themselves — and only the strongest made it to the end."

The experience so rattled Caldwell that, just days later, she launched a Facebook group called "Minneapolis Vaccine Hunters" to help seniors and others navigate the chaotic and often maddening process of securing vaccine appointments.

Those fortunate enough to get the shots, she imagined, could share helpful tips on how they accomplished the feat — injecting some compassion into the intense competition for the scarce vaccines. To date, 13% of Minnesota's population has received at least one shot of the two vaccines, according to a state dashboard.

Within a week, thousands of Minnesotans frustrated by false leads, glitchy websites, provider wait lists and dead ends poured into Caldwell's Facebook group, turning it into a vital clearinghouse of real-time information that could not be found on government or pharmacy websites.

The group also has shone a light on deeper problems with the vaccine distribution system, including troubling disparities in access to the shots and gaps in the state's vaccine rollout. Those with chronic health problems or disabilities are feeling increasingly left behind in the rush to inoculate seniors and health care workers against the virus that has killed more than 6,400 Minnesotans and infected nearly 480,000.

A 63-year-old man diagnosed with stage 4 lung cancer told of being turned down for the vaccine because of his age, even after saying he was "desperate and willing to drive just about anywhere."

A man who had two kidney transplants and a weakened immune system described his efforts to get an appointment online — to no avail.

Parents with adult children with Down syndrome wrote of being rejected again and again despite research showing that people with the chromosomal condition are 10 times more likely to die from COVID-19 than the general population.

A stay-at-home mother with three young children, Caldwell has found herself thrust into a high-stakes position of helping people navigate life-or-death decisions, with no playbook to lean on. Her Facebook group has swelled from a few dozen people two weeks ago to nearly 9,000 members. Scrambling to keep up, she has recruited four volunteers to help monitor the site while she cares for her children, including a 7-month-old infant, Lilah, who just learned to crawl and a 5-year-old, Benjamin, with a developmental disability.

On a snowy afternoon last week, Caldwell handed out sippy cups and peanut butter-and-honey sandwiches to her kids while darting about the living room looking for her lost smartphone. Responding to queries on her fast-growing Facebook page would have to wait until their 2 p.m. naptime, she decided.

"It's become painfully clear how many people are still trying to figure out this dysfunctional system," she said. "It's been inspiring and disheartening, all at once."

Early on, Caldwell's site became a destination for people pursuing extra doses of the vaccine — often referred to as "vaccine chasers." Clinics and pharmacies sometimes have soon-to-expire doses left over at the end of the day, and people have been willing to drive hundreds of miles and queue up for hours in the hope of getting a lucky break.

This unofficial back door to vaccines has raised moral concerns because it has enabled some younger and healthier people to get the shots even though they may not qualify under Minnesota's phased distribution system.

Yet many vaccine hunters, especially those with serious health problems, have no ethical qualms about getting doses that would otherwise go to waste.

Camille Gage, a Minneapolis-based artist and writer, wasted no time when she saw a posting on Caldwell's site about leftover doses at the Minneapolis Convention Center. She and her husband Patrick Mulligan threw on their winter boots and parkas and arrived downtown within 15 minutes only to discover about 30 people already waiting for leftover doses in the building's atrium.

Gage, who is 64 and has a form of asthma, was determined to stay to the end. Finally, at about 10:30 p.m., a young man with a laptop emerged with good news: Everyone scheduled for shots had been vaccinated, and there were just enough doses left over to inoculate the dozen or so people still patiently waiting.

"Our eyes were as big as saucers, we were so excited," Gage said. "I think it's better for some people to queue up with the understanding that it might all be for naught than to waste a single dose."

By last week, the Facebook group was bursting with stories of people getting shots through shared tips. An 80-year-old cancer survivor with chronic obstructive pulmonary disease (COPD) gushed, "OMG — thank you, thank you, thank you," after she finally got a vaccine appointment through information on the site. "I was so afraid I wouldn't get a shot until summer," she wrote.

While invigorated by such accounts, Caldwell also is troubled by reports that racial and ethnic minority groups are being vaccinated at lower rates. And she has been closely monitoring her site for signs that vaccines meant for communities of color are being snatched up by people living outside those areas.

"I want to keep this local," said Caldwell, whose husband is Black. "People should not be driving in from Eden Prairie for a vaccine clinic that was meant for a specific church in a specific neighborhood."

As hundreds of people pour into the Facebook group, the site has taken on a life of its own, becoming a depository of advice on how to navigate the complicated patchwork of websites and portals to secure appointments. Many seniors and their loved ones are spending hours each day on pharmacy and clinic websites each with its separate sign-up system and methods for posting available appointments. A single well-timed tip can save a person days of searching.

Katie Bowman posted a plea for help after spending weeks trying fruitlessly to secure the vaccine for her 82-year-old father, a cancer survivor and electrician. Moments later, a fellow member of the Facebook group alerted Bowman that shots had just become available at a local Sam's Club store. Within 20 minutes, Bowman landed an appointment.

"A huge weight was lifted off our shoulders," said Bowman, who lives in Mounds View and works as a television programming coordinator.

While relieved, Bowman said she is worried about older seniors who lack computer skills and may not have relatives who can help them scour websites for appointments. Some may be waiting weeks for their clinics to call them, while others are getting the shots because they are better connected or more tech-savvy, she said.

At times, the pursuit of the scarce shots reminds Bowman of the dark invocation from "The Hunger Games," in which competitors are told, "May the odds be ever in your favor."

"I feel like we're fighting against each other and yet cheering each other on," she said. "I want my Dad to slide in there first, but I want everyone else to slide in there first, too."

Correction: A previous version misidentified the name of the Facebook group.