MISSION, Kan. (AP) — When COVID-19 patients inundated St. Louis hospitals, respiratory therapists arriving for yet another grueling shift with a dwindling supply of ventilators would often glance at their assignments and cry, heading into the locker room to collect themselves.

“They were like, ‘Man, another 12 hours of this slog of these on-the-verge-of-death patients who could go at any moment.’ And just knowing that they had to take care of them with that kind of stress in the back of their head,’” recalled Joe Kowalczyk, a respiratory therapist who sometimes works in a supervisory role.

Now the number of people hospitalized with COVID-19 in the U.S. has dropped by 80,000 in six weeks, and 17% of the nation’s adult population has gotten at least one dose of a vaccine, providing some relief to front-line workers like Kowalczyk. On his most recent shift at Mercy Hospital St. Louis, there were only about 20 coronavirus patients, down from as many as 100 at the peak of the winter surge.

“It is so weird to look back on it,” he said. “Everyone was hitting their wit’s end definitely toward the end just because we had been doing it for so long at the end of year.”

The U.S. has seen a dramatic turnaround since December and January, when hospitals were teeming with patients after holiday gatherings and pandemic fatigue caused a surge in cases and deaths. Health officials acknowledge the improvement but point out that hospitalizations are still at about the same level as earlier peaks in April and July and right before the crisis worsened in November. Deaths are still persistently high, though much lower than the peak in early January, when they sometimes exceeded 4,000 per day.

Hospitalizations in Missouri were hovering around 3,000 a day during a stretch from late November into January but have since fallen about 60%. As of Monday, 1,202 people were hospitalized, according to state data.

In Wisconsin, hospitalizations dropped dramatically over the last three and a half months, from a high of 2,277 patients on Nov. 17 to 355 on Wednesday, according to the Wisconsin Hospital Association. And the patients who are hospitalized are not as sick. The number of patients in intensive care has dropped 81% since Nov. 16.

State health officials on Feb. 15 removed all staff from a field hospital set up in October at the state fairgrounds in suburban Milwaukee. They have stopped short of dismantling the facility out of concern that the state could experience a surge in cases sparked by variants of the virus that causes COVID-19.

“It’s a balancing act. You don’t want to close it too soon until you really believe we’re on the other side of this pandemic, yet we don’t want to tie up (the fairgrounds) too long if we’re truly not going to need the facility,” state Department of Health Services Deputy Secretary Julie Willems Van Dijk said.

Behind the overall positive trends in hospitalizations are worrisome hints that the worst may not be over, said Ali Mokdad, professor of health metrics sciences at the University of Washington in Seattle.

“In the past week, we’re seeing the slowdown of the decline,” Mokdad said. In many states, hospitalizations are leveling off or actually rising.

The biggest driver in the overall decline in U.S. hospitalizations is people’s behavior in December and January, Mokdad said. For the first time in the U.S., the shape of the wave is symmetrical, with the decline as steep as the rise.

“This didn’t happen before in the previous two waves,” Mokdad said. “For us, in the business, it’s like ‘Wow we are doing something really good right now.’”

In Minnesota, non-intensive care hospitalizations dropped from around 1,400 in late November to just 233 as of Tuesday. The number of intensive care patients has dropped about 85% since early December to just 59 patients on Tuesday, according to state data.

Hospitalizations in Illinois hovered around 6,000 patients for several days in late November but fell to 1,488 by Monday, a decrease of about 75%. The number of patients in intensive care has dropped as well, from 1,224 on Nov. 25 to just 361 on Monday, according to the state health department.

In hard-hit California, hospitalizations have dropped a stunning 70% since January, from 22,821 patients on Jan. 5 to 6,764 on Tuesday. The number of patients in intensive care has fallen from a high of 4,971 on Jan. 10 to 1,842 as of Tuesday, according to state data.

In Kansas, where many rural hospitals lack ventilators, the situation was so dire at one point that patients were being flown hundreds of miles for treatment.

But the number of hospitalizations in the state has dropped nearly 84%, from 1,282 on Dec. 2 to 208 on Sunday, according to the state health department. More than 300 people were in intensive care in December; that’s down to just 50 now, state data shows.

“It has just kind of been quiet out here with COVID,” said physician assistant Ben Kimball, who works primarily at Graham County Hospital in Hill City, a town of about 1,500 in rural northwest Kansas.

At the peak of the surge, he once resorted to flying a patient to a hospital in Denver, about 250 miles (402 kilometers) away. All the closer hospitals capable of providing more advanced care were full and turning away patients.

“We are pretty fortunate, I think,” he said. “I can definitely feel that things are getting better. We aren’t constantly struggling for bed space. We have had a few overnight observation COVID patients, but we haven’t sent anyone out in a while.”

Kris Mathews, the administrator of Decatur Health, a small hospital in rural northwest Kansas, also spent hours on the phone arranging transfers for patients at the peak of the surge. His staff fell ill themselves, and those who were well worked overtime caring for coronavirus patients.

“I could feel the staff’s weariness and fatigue,” he wrote. “Nobody complained to me about it, but I could see and feel them burning out.”

Now it’s been weeks since the hospital cared for a coronavirus inpatient. Thinking back, he said, “I couldn’t be more damn proud.”