As two physicians on the front line of Utah’s coronavirus pandemic talked about the potential benefits of blood plasma from recovered patients, a researcher Monday worried studies planned here could be impaired by wider use of the treatment.

The Food and Drug Administration on Sunday issued an emergency authorization for doctors to give patients blood plasma containing antibodies against the virus. The order bypassed much of the scientific rigor that typically comes with government approval.

Some of that rigor is due to happen at the University of Utah.

“We don’t have the most robust data to know if convalescent plasma works,” said Dr. Emily Spivak, an associate professor of medicine in infectious diseases at University of Utah Health.

Spivak acknowledged there is some promising early data but said controlled studies, including those comparing the plasma to a placebo, are needed to determine if plasma is effective and for which patients. At the moment, the data is showing patients who received plasma are only percentage points more likely to survive the virus than those who didn’t get plasma.

“This is not a slam-dunk cure-all,” Spivak said.

(Leah Hogsten | The Salt Lake Tribune) l-r Dr. Brandon Webb, chair of Intermountain Healthcare’s COVID-19 Therapeutics team and Dr. Daanish Hoda, a hematology expert and director of the Intermountain Hematologic Malignacy Department, April 21, 2020.

Five hundred patients at Intermountain Healthcare hospitals have received the plasma through a pilot program approved by the FDA and administered by the Mayo Clinic. In an online news conference Monday, Dr. Brandon Webb, chairman of Intermountain’s COVID-19 Therapeutics team, said more study is needed to determine the best way to use plasma, but he also expressed enthusiasm at more patients having access to the treatment.

“We have some data,” Webb said, “from the Mayo Clinic program that suggests, as we expected, convalescent plasma has a good safety profile.”

Utah coronavirus patients have been receiving blood plasma since April. The first patient was Cynthia Lemus, a 24-year-old flight attendant from Magna who was in a coma and on a ventilator when she received the antibodies.

(screenshot) Cynthia Lemus, with her husband Moises Lemus, talks about her experience with covid-19 and plasma treatmentduring a news conference on May 1, 2020.

Lemus joined Webb in the news conference Monday. She said she still has some coughing and discomfort in her lungs but otherwise feels fine.

“My energy’s back,” Lemus said. “I’m able to go throughout my day and everything.”

Plasma hasn’t worked for everyone. Carol and John Moody, of Sandy, were diagnosed with COVID-19 in May. Both suffered complications and received plasma transfusions along with other experimental treatments, their family has said.

John Moody survived. Carol Moody died May 21. She was 71.

Why the plasma might work for one patient and not another is one of the questions scientists still need to answer. Preexisting conditions, genetics and how soon the plasma is administered after diagnosis are all possible factors, Spivak said.

(Photo courtesy of Robert Moody) John and Carol Moody, of Sandy, both contracted COVID-19. John Moody survived. Carol Moody did not.

With widespread use of plasma, she worries patients won’t want to enroll in a study that compares plasma to a placebo — the patients might see not getting the plasma as a risk.

“It becomes even harder to get the best type of evidence and data,” Spivak said.

She also worries some people will interpret the plasma approval as a cure and cease social distancing, take off their masks and practice bad hygiene.

Three plasma studies are planned at the U., Spivak said. One due to start soon will look at whether giving plasma to emergency room patients who don’t need to be admitted reduces the severity of their COVID-19 symptoms and allows them to recover at home.

Another trial will compare plasma versus a placebo for outpatients with COVID-19. A related trial will examine the potential for plasma to prevent people who have had a high-risk exposure from getting the virus.

Dr. Daanish Hoda, director of Intermountain Healthcare’s Hematologic Malignancy Department, said some physicians might recommend their patients participate in a placebo study. He said some early data shows it’s better to get a plasma donation with a high volume of antibodies, but not every plasma donation from a recovered patient contains that high volume.

FILE - In this Friday, June 12, 2020 file photo, a doctor holds a bag of blood plasma donated by a COVID-19 survivor at at blood bank in La Paz, Bolivia. The U.S. Food and Drug Administration authorized the use of blood plasma for what's called “emergency use” during the coronavirus pandemic, but the World Health Organization (WHO) on Monday AUG. 24, 2020, cautioned that using blood plasma from COVID-19 survivors to treat other patients is still considered an experimental therapy. (AP Photo/Juan Karita, FILE)

The level of antibodies will be controlled in a placebo study, Hoda said, and patients might be more likely to get a high-volume donation even when there’s a 50% chance of getting no antibodies at all.

Utahns who have developed antibodies — including Democratic U.S. Rep. Ben McAdams — have donated their plasma to be used in other patients. Hoda said an already thin supply of plasma is likely to get stretched more with the FDA approval.

Hoda and Lemus on Monday encouraged recovered patients to donate their plasma through the American Red Cross or other organizations.