STAMFORD — Researchers are isolating antibodies in people who’ve recovered from the coronavirus to see if they can help the hundreds of hospital patients struggling with the sometimes-deadly respiratory infection.

The effort is underway at Stamford Health — which is conducting Connecticut’s first clinical trial — and at Nuvance Health in Danbury and Norwalk, which is collecting the plasma of recovered COVID-19 patients for a similar study later this month.

“Plasma therapy has a long history of success in helping patients with diseases such as polio, measles and even the flu in their recovery” said Dr. Paul Sachs, director of pulmonary medicine at Stamford Health and a principal investigator for the trial. “Pilot studies at other organizations have shown promise, and we hope that we’ll see those successes replicated for COVID-19.”

The federal Food and Drug Administration agrees, up to a point.

“Although promising, convalescent plasma has not yet been shown to be effective in COVID-19,” the FDA said in a statement late last week. “It is therefore important to determine through clinical trials, before routinely administering convalescent plasma to patients with COVID-19, that it is safe and effective to do so.”

To assist those trials in Stamford and across the country, the American Red Cross is looking for plasma donors who are fully recovered from COVID-19.

“People who have fully recovered from COVID-19 have antibodies in their plasma that can attack the virus,” the Red Cross said in a statement. “This convalescent plasma is being evaluated as treatment for patients seriously ill with COVID-19.”

At the same time, Nuvance Health has launched a blood plasma program to treat critically ill COVID-19 patients. The network’s Connecticut hospitals include Danbury and Norwalk hospitals, and its New York hospitals include Vassar Brothers Medical Center in Poughkeepsie.

Plasma donors are asked to register by filling out a questionnaire.

Stamford Health, which runs Stamford Hospital, has about 30 people sick with coronavirus who are eligible for the plasma therapy, several of whom could receive the simple treatment as soon as the end of the week.

“The antibodies are inside the plasma and the plasma is transfused directly into sick patients,” said Suzanne Rose, Stamford Health’s Office of Research director, and the study sub-investigator. “This could be revolutionary, because there’s very few side effects, and we don’t have to give somebody drugs to help their body fight harder against the infection.”

The therapy involves the transfusion of two units of plasma that has been analyzed tested. The first unit is given slowly over two hours to ensure the patient’s body doesn’t reject it. A second unit of plasma is then given.

The Stamford study is similar to trials that have begun across the country, including a large-scale trial at Mayo Clinic in Minnesota, where the focus is on helping hospitalized patients with “severe or life-threatening COVID-19.”

Closer to home, the hope is to lessen the severity of the illness and shorten the time people need to be hospitalized in Stamford. The study will compare patients who receive plasma treatment to COVID-19 patients who have been at Stamford Hospital without the therapy prior to the trial, Rose said.

“It is very exciting because we hope to get a lot data and definitively answer some of the questions around convalescent plasma therapy, which has been around for years.”

Connecticut, in solidarity with the rest of the country and the world, is fighting an unprecedented pandemic that has infected more than 7,700 people in the state since March 8, and killed 326.

The majority of people with the infection have moderate symptoms and recover. The elderly and those in frail health are most susceptible to serious illness and death.

rryser@newstimes.com 203-731-3342