"It's not that I don't want to. But the patients keep on coming," said Varon, a critical care doctor and chief of staff at United Memorial Medical Center in Houston.
It used to be worse. After Covid-19 crushed the hospital earlier this year, his team juggled as many as 88 patients at once with the disease. But in the last few weeks, as few as 10 coronavirus patients needed their care.
"Then the last five days have been hell. We're getting a lot of patients. And the patients are coming in very, very ill."
For example, ventilators -- once widely used early in the pandemic -- are now used less frequently, as doctors have learned how they may injure Covid-19 lungs.
But in some places, nurses still don't have enough protective equipment. People keep flouting masks and social distancing. And rapid, at-home testing remains a pipe dream.
Here's where experts say the US stands as it enters the next phase of the Covid-19 pandemic.
What doctors have learned about treatments
Many Covid-19 patients who entered hospitals earlier this year did not make it out alive.
Since then, "the death rate per case ... has definitely dropped. And that's a tribute to modern medicine," epidemiologist Dr. Larry Brilliant said.
But as more patients survive, many are also stuck at the hospital with long-term complications.
"Before, people would come in when they were just dying. Now, we keep them alive. But many of them have very bad lung disease, and they will require long-term care," Varon said.
These days, Varon said he's again seeing patients come in with more advanced Covid-19.
"Part of that is based on what I call Covid fatigue syndrome. People are tired ... they are looking the other way. If they have symptoms, (they think) it's no big deal. And then by the time they come to us, they are very sick."
It's critical to seek medical care immediately because "at the early start of the illness when you have Covid, the virus is multiplying like there is no tomorrow," Varon said.
"The evidence on convalescent plasma as a treatment for severe cases of COVID-19 is promising but incomplete," Dr. Francis Collins, director of the National Institutes of Health, said in a written statement last month.
For now, the NIH treatment guidelines don't recommend for or against using convalescent plasma to treat Covid-19.
But this month, the World Health Organization said remdesivir has "little or no effect on mortality" for patients hospitalized with Covid-19 and it doesn't seem to help patients recover any faster, either.
Despite the ever-evolving research, "we have learned a lot," Varon said. "What I do today is not what I was doing three, four months ago."
Why ventilators might be bad for Covid-19
With many patients, "we learned that putting somebody on a ventilator is basically signing their death sentence," Varon said.
"We learned the hard way that putting pressure into your lungs in somebody that has damaged lungs, like Covid patients, was creating more injury than benefit."
Brilliant said it's "good news" that hospitals aren't using ventilators as much on Covid-19 patients.
"Doctors are not shoving ventilators down people's throats quite as quickly. That's a wonderful thing," he said.
"You know how everybody thinks that an oxygen (level) of more than 90% is good, and that's where you need to stay? We learned that because we were causing so much damage (with ventilators), maybe we should tolerate a little lower oxygen. So if it came down to 85%, we probably would be OK."
That's different from his previous methods with non-coronavirus patients, in which those with "85% (oxygen) gets a (breathing) tube. 89% gets a tube. So we learned that we can actually allow lower oxygen concentrations."
Doctors have also learned that laying patients facedown on their stomachs can help increase the amount of oxygen that's getting to their lungs.
"We're saving lives with this," Dr. Mangala Narasimhan, regional director for critical care at Northwell Health in New York, said in April.
"It's such a simple thing to do, and we've seen remarkable improvement. We can see it for every single patient."
When patients lie on their backs, the weight of the body effectively squishes some parts of the lungs.
But "by putting them on their stomachs, we're opening up parts of the lung that weren't open before," said Dr. Kathryn Hibbert, director of the medical ICU at Massachusetts General Hospital.
How hospital capacity has improved -- or not
Across the country, many hospitals are already starting to max out due to soaring Covid-19 cases, said emergency medicine physician Dr. Megan Ranney, who directs the Brown-Lifespan Center for Digital Health in Rhode Island.
"My colleagues across the country are sharing stories of their ERs getting overwhelmed, their ICUs being full, running out of nursing staff because their nurses are getting sick," Ranney said.
"We are facing the same situation that we were in in April and May in the Northeast and in July in the South. And the trouble now is that we're seeing it literally across the country," she said.
"We're hearing similar stories from my colleagues literally across the country, including here in the Northeast. We're starting to see hospitalizations tick up. We are seeing people who are much sicker than they have been since that first wave in the Northeast in the spring."
Infectious disease specialist Dr. Aileen Marty, a professor at Florida International University, said Covid-19 hospital admissions are going up in her state.
"We're balancing those by being able to get people out of the hospital sooner than we were because we've learned a lot," she said. "But it's still happening."
Some health care workers still don't have enough PPE
Fast-forward to October, and PPE shortages are still a concern, according to National Nurses United, the largest union of registered nurses in the US.
"We must currently rely on firsthand accounts from our members because hospitals are only required to report PPE stock levels to the US Department of Health and Human Services, which does not publicly release the data," the union said in a written statement.
"The lack of transparency on PPE stock and supply is outrageous."
Without sufficient PPE, health care workers treating coronavirus patients are at high risk because "the viral load -- the amount of virus -- does determine the severity of your illness," said emergency medicine physician Dr. Leana Wen, a former Baltimore health commissioner.
"So that could happen in the case of health care workers who are exposed to a lot more Covid-19 as a result of their work -- that they get more severely ill."
"Let's be clear that this pandemic is not over. Cases are rising again in many areas of the country," the union said this week.
"We are still demanding that President Trump activate the Defense Production Act to mass produce PPE, and that federal OSHA promulgate an emergency temporary standard on infectious diseases to mandate that our employers give nurses optimal PPE."
Insufficient testing is holding the US back
"We have more people infected. We have more states, we have our rural areas affected. Once again, we have hospitals filling up -- this time, not just in our major metropolitan areas, but in more rural areas. The death rates are going up," he said.
Americans should have quick, easy access to testing, Haseltine said. But that's still not the case in many places.
"One of my grandchildren had a cold. And we had to get tested. It was murderous. In New York City, there were two places that could do the rapid tests," he said. "Two places in Manhattan. That is unbelievable. And we had to wait hours -- six hours just to get tested."
Since the beginning of the pandemic, "we are a little bit better at testing, (but) not much," Haseltine said.
Haseltine said tests have gotten more accurate in recent months, and some are more affordable -- as cheap as 50 cents.
"My recommendation is make (tests) universally available to every household, and if somebody in the household is positive ... we make it economically possible by paying them to stay home -- the whole family -- for 14 days," Haseltine said.
"That could end this epidemic within three to four months."
Haseltine said he has calculated the estimated costs for "a program to get everybody three or four months' worth of free tests -- they can test everybody in their family -- and pay everybody $500 to stay home for two weeks, for their entire family" if someone tests positive.
This plan is "comparatively inexpensive, compared to what we are putting up with," Haseltine said. "If we decided to push the button now, go full-speed ahead, we could probably have this epidemic over and done with by March."
So why don't we all have Covid-19 tests in our medicine cabinets yet?
"From the President on down, most of the official leadership has been deeply misguided," Haseltine said. "They have focused first on treatment and not on prevention."
Adm. Brett Giroir, the White House testing czar, said Covid-19 testing has improved dramatically in the US.
But Giroir has repeatedly said, "We can't test our way out of this" pandemic.
"He's right in a limited way," Haseltine said. "He's right that testing isn't enough. Testing plus isolation is the way to drive this down to zero ... voluntary testing followed by paid isolation."
As for the theory that Covid-19 cases are surging just because of increased testing, "that is absolutely not the case," Haseltine said.
"That is not why hospitalizations are going up. That's not why deaths are going up."
'A war against stupidity'
Doctors are "better prepared. We're better studied. But patients are coming in. And people are being stupid," said Varon, the critical care doctor who's worked every day for seven months.
"I am fighting two wars. I am fighting a war against Covid, and I'm fighting a war against stupidity. It is unbelievable."
After spending 16 to 20 hours a day at work, Varon said he's disgusted by images of people socializing without face masks.
"I just had one of the worst weekends (at work) I've had for a very long period of time," he said. "This is not a hoax. This is real. And anybody who doesn't believe me, they can come and spend a day with me."
As for young people, "if you think nothing bad is going to happen to you, you are wrong," he said. "And I would hate to see you on long-term oxygen or being crippled, having to be on a wheelchair or a walker for the rest of your life."
That's not hyperbole.
He vividly recalls a 32-year-old man with no pre-existing conditions and was "healthy as a horse" -- until he came down with coronavirus.
"He ended up here with us in the hospital. He was a very sad story," Varon said. "He spent with us close to 70 days and eventually went home on oxygen -- probably for the rest of his life."
But there are ways to get out of this pandemic, Haseltine said.
"The first thing that we have to do right away is for everybody to take what you hear every public health official say, which is wear a mask and socially distance," he said.
"The second thing is we have to have a federal policy that we are going to do everything we can to get rapid tests in everybody's hands immediately. And we are going to pay people to stay home so they don't infect other people when they are potentially infectious."
If we take those steps, he said, "we could put this close to zero in four months."
CNN's Jen Christensen and Elizabeth Cohen contributed to this report.