Five years after COVID-19 was declared a pandemic, Registered Nurse Nicole Baca still visits an infusion center every week to have a mixture of water and other nutrients injected into her bloodstream.

“The treatments help increase my blood volume, and that’s what helps keep me from passing out,” the El Cajon, California, resident explained.

Such visits would have been unthinkable in 2019, when she went to the gym three times per week and regularly traveled, backpacking from one destination to the next.

Today, she’s grateful if she can take a walk at Southern California’s Ocean Beach with her husband, an act that requires meticulous pre-planning to avoid the racing pulse that can make her dangerously dizzy.

“Once, I had an episode where I almost passed out in a neighbor’s driveway,” she said. “I bent down to pick something up that was on the ground, and everything started to turn white.”

Baca, 40, is among those who have developed life-limiting symptoms after an encounter with pandemic coronavirus, a syndrome that most call long COVID. Government surveys show that about 5 percent — roughly 17 million Americans — are generally suffering COVID-19 symptoms that have lasted three months or more at any given time. Somewhere around 18 percent of the U.S. population, about 61 million people, report having experienced lingering symptoms. Though there is no perfect count of how many, like Baca, have had their symptoms linger for years, about 1.5 percent, roughly 5 million people, have said their symptoms are severe enough to significantly limit their activities.

This never-ending fight started in June 2020 when she found herself becoming strangely confused during a shift in a COVID-19 unit at the San Diego hospital where she worked. These were the days when health care workers were isolating themselves from their families, often staying in hotel rooms when off duty.

“My last day at work, I caught myself forgetting what I was doing, and I felt like I was on cold medicine, but I wasn’t,” she said. “I developed shortness of breath, a fever, fatigue, extreme bone pain, cough, diarrhea and dizziness.

“I was stumbling into the walls of my hotel room. Weirdly enough, I never lost my sense of taste or smell like most people did at the time.”

Most see such symptoms gradually resolve. For Baca, they worsened, permanently causing her body to overreact to small changes in elevation. Just standing up sends her pulse racing, the heart monitor in her Apple Watch warning of a dangerously erratic heartbeat. Such cardiac overcorrection causes her blood pressure to drop, increasing the chances that she will faint.

It took plenty of internet research and constant insistence with medical specialists to affix a diagnosis to the symptoms she has continued to experience. But, eventually, her blood pressure changes in response to elevation changes arrived at POTS, an acronym for a medical condition called postural orthostatic tachycardia syndrome.

Though this condition is not well understood, it is known to affect more women than men and seems to appear after severe infection, leading researchers to suspect that it is a form of dysregulation of the autonomous nervous system.

Researchers have observed a correlation between COVID-19 and POTS, with an initial study showing a significant increase in diagnosis after coronavirus infection and a minor increase after vaccination, though additional research would be necessary to prove a link.

Because county contact tracers were able to trace her infection to a specific patient she cared for when she got sick, Baca said she did receive workers’ compensation coverage for her medical care. However, she has been unable to resume her full-time career in nursing. At the time the pandemic hit, she said, she was about to transfer to a new position as an operating room nurse. But before she could transfer out of her previous unit, one that cared for surgical and oncology patients, it was converted to a COVID-19 ward and her transfer was put on hold.

After beginning to take medication to regulate her heartbeat, she was able to start working in operating rooms two days per week, though that didn’t last.

“I had an episode at work where I almost passed out in the OR, and my boss found me in the break room,” she said. “I checked into the emergency department, and they found that I was having a flare of my POTS symptoms.”

What she thought would be a week off work before resuming her job turned into two years on disability. Today, she works one day a week doing case management, but her dream of assisting surgeons in operating rooms is long gone.

“They’ve basically said that, because of my condition, I’m too much of a liability in the operating room, if I was to have a flare of my symptoms,” she said. “According to my doctors and workers comp, I’m not allowed to return to the operating room, so that part of my job is done.”

The most discouraging development, she adds, is her experience with the pharmaceutical industry. She and several others experiencing debilitating POTS symptoms were involved in a clinical trial for a drug that had good results in better regulating their nervous systems. One year in, she said, the trial was abruptly canceled, leaving many to regress.

“There were people who were wheelchair bound — I was pretty much homebound — not able to do much, not able to work, and by being in that study their lives turned around,” she said.

Many, she said, were heartbroken to learn that the company making the drug had canceled its clinical trial; attempts to get doses under the nation’s compassionate use laws were denied. The experience was so frustrating that she and others recently traveled to Washington, D.C., to advocate for better long COVID-19 research funding.

Five years after the pandemic, Baca said, it has begun to feel like the public just is not interested in understanding the syndrome that has so permanently changed her life. While she got sick literally caring for others during a global pandemic, that sacrifice doesn’t seem to count for much these days, especially since her POTS symptoms don’t affect her outward appearance.

Because POTS is not common, and it is difficult to diagnose, she said she has had to continually educate her own doctors about the situation, arriving pre-armed with a sheaf of medical studies to make her case.

And those close to her have been even less understanding.

“I have lost relationships with family members and with friends of mine over my condition,” she said. “I have a family member who is very much a conspiracy theorist who doesn’t think COVID was real, who thinks that vaccines are a scam and who doesn’t think that long COVID is a real thing.”

But there has also been a bit of a silver lining. Experiencing long COVID has put her in contact with many others stuck in the same fight.

“I’m thankful for the true friends in my life,” she said. “I have now created a new tribe of friends that are supportive, and I am very grateful for that.”

Pandemic coronavirus continues to infect millions across the world annually. While it looked like the most recent subtypes of the virus, children of the Omicron strain that first appeared in late 2021, might be producing fewer long COVID cases, that does not appear to be the case.

Dr. Marlene Millen, chief medical information officer of ambulatory care at UC San Diego Heath, said new cases definitely continue to arrive, though they have been observed to be more common among those who are not vaccinated.

“We’re definitely still seeing new cases pop up,” Millen said. “In fact, it’s one of the reasons I’ve pushed vaccination at least annually, because the folks that have been vaccinated in the last year, you know, we’ve noticed much less long COVID in.

“I usually get a couple of new cases every month or two where they’ve had COVID in the last three to six months and they’re just not recovering.”

Though she managed to avoid getting sick working through the toughest years of the pandemic, Millen said that she finally experienced COVID for herself in 2023. Like others, she experienced brain fog and other symptoms that lingered, not abating for six or seven months and causing her to miss work. She attributes her eventual recovery to the fact that, by the time she became infected, she had already been vaccinated and received two annual booster shots.

The advantage of vaccination in preventing long COVID, she said, seems to be in the fact that a person’s immune system has already been primed to produce what’s necessary to fight off the virus, meaning that a less-forceful reaction is necessary, especially in terms of widespread inflammation in the body, when an infection occurs. There is also a strong correlation between long COVID incidence and the presence of other chronic diseases at the time of infection.

“Definitely, if you have underlying medical conditions and you’re not getting the vaccine, you’re going to be much more at risk for long COVID,” Millen said.