Where there had once been long lines of cars filled with people desperate for shots, there was now a huge, mostly empty parking lot dotted with orange traffic cones.

On this Saturday in July, Maryland’s longest-running mass vaccination site at Six Flags America was closing. And even as nurses continued to give a couple hundred lifesaving shots in one tent, staff were working to break down the three others that had been needed back when the daily total was in the thousands.

The propane heaters that helped keep nurses warm during the winter months had been disconnected; the umbrellas that shaded security guards on summer days were in boxes; and the orange cones that had guided throngs of vaccine-seekers through the facility were stacked in piles staffers dubbed "cone graveyards."

The day — July 10 — marked the end of the mass vaccination era in Maryland, as the state had slowly demobilized the clinics it set up beginning in February, when people nationwide were clamoring for a scarce supply of shots and lines of cars waiting at Six Flags sometimes stretched three miles down Central Avenue in Bowie.

Across the rest of the country, the tide has also shifted.

Even as cases linked to the delta variant are surging in some parts of the country, mass vaccination sites in Massachusetts, California, New York and elsewhere have all shuttered in recent weeks. With vaccine demand dramatically down, governments have turned away from big operations at places like Six Flags — highly efficient but intimidating in size and somewhat spartan in appearance — in favor of lower-key options like churches and community centers.

More than 342,000 people got vaccinated at the Six Flags, the most of any location in the state. And in total, Maryland is among the top 10 states for vaccination rates, with 63 percent of its population having received at least one dose.

“It’s bittersweet,” said Mark O’Neill, the site manager, as he stood inside the main command tent. “There is a sense of mission accomplished.”

But he said in recent days that he has followed the news about the rise of cases linked to the variant elsewhere in the country. If need be, all the best practices are in place to stand up an operation like Six Flags again.

“We have done it successfully,” he said. “The apparatus to put this back — if God forbid we have to — is there.”

The cast of characters led by O’Neill, who arrived in late May after leading the demobilization of a mass vaccination site on Maryland’s Eastern Shore, came from a variety of state agencies and private companies.

The logistics chief arrived after closing her own business because of the pandemic. A nurse came from treating covid-19 patients at the intensive care unit of a D.C. hospital. The National Guard member who transported the vaccine vials was on leave from his tree care company. The woman running vaccinations for the disabled had been let go from her job at the shuttered Kennedy Center.

Over the course of five months of long hours and sometimes tough conditions, they had become an unlikely family of sorts, united in their shared mission of getting as many Marylanders vaccinated as quickly as possible.

It wasn’t easy. There were the storms, the traffic and the lack of running water. There were angry outbursts about long waits, and there was frustration in the majority-Black county where Six Flags is located that so many shots initially were going to outsiders.

Nonetheless, even on the hardest days, workers at Six Flags thought of those suffering in covid wards and grieving at funeral homes, and remembered why they were there.

On closing day, Ann Gerald, the logistics chief, was speed-walking across the parking lot, clipboard in hand.

Gerald, who had been recruited to the site from Austin, where she was conducting search and rescue missions, paused when she saw Johnathan Pitts ambling toward her in his orange safety vest. She asked Pitts, who had been greeting and directing cars since the very beginning, how he was doing.

“Are you happy or sad it’s the last day?” Pitts, 31, asked in reply. “In between, right?”

“I feel a sense of accomplishment, to be honest with you,” said Gerald, 48. “What about you?”

Smiling, he agreed: “Accomplished,” he said. “Now that you say that.”

'Worth it'

On the February morning that the Six Flags site launched, people eager to get vaccinated snapped up all 10,000 appointments within two hours.

The state was still recovering from a winter surge of covid-19 cases, with more than 1,700 Marylanders hospitalized. Competition for the small amount of available vaccine was fierce.

When Gov. Larry Hogan (R) announced the opening of Six Flags and the other initial mass vaccination sites, before the state had enough vaccine to meet the demand, he urged patience. “The truth is that this is not going to magically get better overnight,” he said.

The governor talked on opening day about the importance of equity in the vaccine rollout. Prince George’s, which is more than 80 percent Black and Latino, at the time had the lowest vaccination rate of any jurisdiction in Maryland.

But most appointments at Six Flags during that first month would go to residents from the wealthier, Whiter suburbs of Howard, Montgomery and Anne Arundel counties, who worked the phones and the Internet to get them.

Part of the problem was access, and part was hesitancy.

Donna-Lee Baker understood both. The 35-year-old nurse, who began working at the Six Flags site in February and lives 10 minutes away in Hyattsville, had friends and family initially struggle with the online system to secure appointments at the site. And Baker, who is Black, said she delayed getting her own vaccination for months because of concerns she had about its safety.

But she had seen the effects of coronavirus up close while working in the intensive care unit at MedStar Washington Hospital Center, including during the pandemic’s initial spring surge, when she was pregnant.

After witnessing so much death, she decided she wanted to be a part of the drive to prevent it. In the beginning, Baker was vaccinating people during 12-hour shifts, six days a week — at times so cold that she and other nurses chugged coffee to stay warm.

“Your fingers and toes would be frozen,” she said. “But it would be worth it.”

From a surge to a trickle

After a rocky start slowed by both supply constraints and winter storms, by April, the Six Flags site was doing at least 3,000 shots per day.

That month — its peak — there were 12 lanes with 48 vaccine stations and about 280 staff members making it happen, including 40 members of the National Guard.

Sgt. William Ruckman, who was on leave from the tree care company where he works in Carroll County, delivered vaccine doses from the pharmacy to the medical tents. He said during the busiest days — when the site was going through hundreds of vials per hour — he took that trip every 15 minutes.

On Saturday, April 17, its busiest day, 4,866 shots were given out.

The ramp-up had been made possible because of a slew of people working seven-day weeks, including Nikkia Redd. The 39-year-old’s position as the assistant manager of usher services at the Kennedy Center was terminated because of virus restrictions, and she was recruited to join the Six Flags site at the end of March.

Redd, who lives in Southeast D.C., had been tasked with overseeing vaccinations for people with disabilities, and for those who do not speak English, including ensuring that federal disability laws were adhered to. Trying to get those people vaccinated through the regular process during the first few weeks had slowed the lines, staff said, and meant they were not given enough one-on-one care.

Redd, who was already familiar with disability laws because she has long been an advocate for her brother, who is paraplegic, got to work setting up a program that filtered those people through their own lane, with nurses equipped to deal with any issues that arose — including people so scared of needles they had to be distracted, and some who had trouble understanding why they were there.

They held hands, massaged shoulders and handed out stress balls. Sometimes, it would take as long as an hour and a half to get one person vaccinated.

In May, Redd and other staff at the site were noticing a declining number of people arriving each day. Part of that had to do with how easy it had become to get a vaccine, which were, by then, available at pharmacies and doctors’ offices. And there was also dwindling interest — part of a national trend that would only become more clear as spring turned to summer and plummeting interest in the vaccine forced officials to revise their goals.

As what had been an onslaught of vaccine-seekers shrank, so too did Redd’s staff, with some nurses heading to parts of the country where vaccination rates are lower and others sent to mobile vaccination clinics elsewhere in Maryland. No longer working such long hours, Baker got to spend more time at home with her 1-year-old son. Ruckman’s trips between the pharmacy and the medical tents went from every 15 minutes, to every 30, then every 45.

A crew of male nurses stopped giving shots and started helping the logistics team deconstruct the site.

On June 3, Hogan announced the “phased demobilization” of the mass vaccination sites. The governor said resources would be shifted to mobile vaccination clinics and community-based initiatives to ensure that every Marylander who wanted a shot got one.

“I said our goal was to put ourselves out of business at these mass vaccination sites,” the governor said. “As one of the most vaccinated states in the country, we are now approaching that point.”

The last day

There was no fanfare on the final day — only a couple hundred people who still needed their shots, and staff trying to wrap their heads around the fact that this really was the end.

Baker, the nurse who had started in the tents and by the final day been promoted to the head of medical operations, made sure her colleagues signed her commemorative hat. Redd reunited with one of the nurses in her unit, who’d left a few weeks earlier and came back to surprise her on the last day.

Gerald, the logistics manager, walked through the parking lot, spotting things that were out of place. An errant cone would have to be moved and a broken chair reported to the state, she said, making a note in her clipboard. Everything must be accounted for.

She had been thinking lately about how any time she felt tired, or frustrated by the challenges of running a site so large, all she had to do was step outside and look at the line of cars filled with people wanting to get vaccinated.

Gerald, who had been enraged by the low vaccination rates in Texas — where only 50 percent of the population has received a first dose — said those moments invariably lifted her spirit.

She’s been frustrated by the recent uptick of covid-19 cases, including in her home of Austin, where restrictions have again been put in place to limit the virus’s spread.

Her fear is that there’s a segment of the population that simply can never be convinced.

“People are going to have to make a choice,” she said. “And it goes beyond political affiliation. This is about science and health.”

In the observation area, a group of nurses were reminiscing with their favorite National Guard member, 19-year-old Noah Dennis.

They remembered vaccinating after Brood X hatched, batting away the cicadas with badminton rackets. The doughnuts that people brought to thank them. Blasting music to keep morale up — including country, Dennis’s favorite.

“This kid right here is awesome,” said nurse Tiana Satchell. “He smiles every day. Rain outside. Cold outside. Bugs outside.”

Stoppp,” Dennis pleaded, with a smile.

Satchell, who said the months at the Six Flags site were the highlight of her nursing career, told Dennis she’d awaked that morning sad to see it close.

“I felt sad,” Dennis agreed. “But I also felt happy that I don’t have to show up here anymore.”

The last appointments were scheduled at 1:15 p.m. Stuck in traffic coming from Silver Spring with their aunt, Javier and Raul Gomez barely made it.

The brothers from Mexico City were the last two people to be vaccinated that day. At the same time as they were getting their shots, nurses were watching as a security guard closed the gate one last time. They broke into cheers. Some started dancing, others snapped selfies.

“We made it,” one said.

“We are done,” another shouted.

Baker looked around and, looking at everyone and no one in particular, said, “Good job, y’all.”

In the back seat of his aunt’s car, Raul Gomez, 22, breathed deeply and looked away as a nurse jabbed the needle into his arm — the last shot to be administered at Six Flags.