News of a promising plasma therapy for COVID-19 brought hope to Kimberly Oleson, so she enrolled her parents. They both have COVID-19, and her father was near death on a ventilator.

Then came the wait. Days passed, and no plasma. Oleson’s father lingered in intensive care at North Memorial Health Hospital. Her mother’s health worsened and required hospitalization last week, too.

A clinical trial organizer by profession, Oleson grew impatient, hoping that the plasma could work as proposed by researchers — triggering the faster release of key immune system cells to beat back the COVID-19 virus.

“If there is a way to bring these super-fighters on board a little earlier, that could be helpful,” she said.

Delays have complicated the launch of a national clinical trial by Mayo Clinic in Rochester to extract plasma that is already primed to fight COVID-19 from people who have recovered from their infections. One limiting factor has been access to confirmatory COVID-19 tests to ensure donors are no longer infected.

Another has been that donors have to be virus-free before they can donate.

“COVID has not been in Minnesota with large numbers thankfully, so we have to wait … for people to be done and be well before they’re able to be brought in to donate,” said Dr. Scott Wright, director of Mayo’s human research protection program.

Mayo is hopeful that such startup issues have been resolved and that donations will surge for a therapy that could prove vital in battling COVID-19, an infectious disease that for now has no proven treatment.

More than 1,300 facilities have signed up, including 40 in Minnesota, to provide plasma to COVID-19 patients. Plasma for local patients is being collected by the American Red Cross.

Donor guidelines require people to be symptom-free for 14 days if they have a COVID-19 follow-up test to confirm the virus is gone, or 28 days without the test, said Red Cross spokeswoman Sue Thesenga.

Nationally, more than 2,300 volunteers have signed up — a number that doubled in the past week. Roughly 750 patients have received plasma under the trial, including 20 in Minnesota, Wright said.

The local recipients include Oleson’s parents, who waited for seven days before receiving it late last week.

“If you’re super, super sick, you might not make it in seven days,” said Oleson, who spoke to the Star Tribune on the condition that her parents, ages 85 and 82, not be identified.

The rapid pace of clinical trials for COVID-19 has been unprecedented, but not without hiccups. The University of Minnesota’s trial of an anti-malaria drug, hydroxychloroquine, has been available for a month but has reached only half of its enrollment goals.

Optimistic appraisals of the drug by President Donald Trump and others have led to aggressive off-label prescribing, even though research has been inconsistent on whether it works in preventing COVID-19 or treating symptoms.

As a result, people aren’t as interested in a trial that might result in them receiving non-medicating placebos rather than the active drug, U officials said.

Still, the U is on target with the trial, said Dr. Timothy Schacker, the medical school’s vice dean for research. “Once the study is done, in two weeks, we will have the answer.”

The U also has been part of a national trial of an experimental antiviral drug, remdesivir, and last week started recruitment for trials of a blood pressure medication, Losartan.

A promising retrospective study came out last week showing that blood pressure drugs inhibit the ability of the virus to latch on and infect healthy cells. But now a trial comparing this drug with a placebo is needed, said Dr. Michael Puskarich, a co-leader of the two Losartan trials.

The trials will study the effect of the drug on people being treated for COVID-19 in outpatient settings or hospitals. Trial sites include the U along with Mayo and Hennepin Healthcare.

Oleson said she is grateful for North Memorial’s efforts to get plasma for her parents.

Whether or not the plasma is the driving force, her parents are getting better. Oleson’s mother left the hospital for home over the weekend.

Oleson and her mother had been making daily calls to her father to give him encouragement, knowing he couldn’t talk while on a ventilator. On Sunday, much to their surprise, he mouthed words back to them. He was off ventilation and improving. It was her parents’ 60th wedding anniversary.

“At first, she just said ‘nothing fancy,’ ” Oleson said of anniversary plans. “Now she said on the phone, ‘I want to go out and I want a good dinner.’ She just raised the stakes, which means she’s feeling better too.”