Convalescent Plasma Is Looking Like A Coronavirus Success Story - BuzzFeed News

US hospitals are now treating around 1,500 patients a day with antibodies found in the blood of COVID-19 survivors.

A nurse holding blood plasma from a person who has recovered from COVID-19, which will be used to help critically ill patients, in Basra, Iraq.

On Monday, federal health officials kicked off two large clinical trials of synthetic antibodies to treat mild, moderate, and hospitalized coronavirus cases.

And the FDA is expected to soon give emergency authorization to treating patients with the “convalescent plasma” of COVID-19 survivors — the part of blood that is rich in antibodies.

A preliminary analysis of data from about 50,000 patients presented to the FDA on Saturday at a Mayo Clinic symposium found a 10% drop in deaths among critically ill hospitalized COVID-19 patients given plasma with higher concentrations of antibodies compared to those given lower dose ones.

Convalescent plasma, the yellowish fluid transfused into patients, is essentially blood stripped of red and white blood cells, leaving behind antibodies, water, salt, and enzymes.

In the coronavirus pandemic, tests to tell convalescent plasma doses with high amounts of antibodies from those with low doses have only been validated in recent months.

In April, the FDA had first promoted antibodies for that stopgap role as US cases started to surge in New York, calling for the Mayo Clinic and blood banks nationwide to deliver convalescent plasma to patients under nationwide emergency use guidelines.

At least 85,000 patients have received convalescent plasma under the program, so far, Mayo Clinic cardiologist Scott Wright told BuzzFeed News.

Ironically, the popularity of convalescent plasma has undermined attempts to verify its effectiveness in fully randomized clinical trials for at least two reasons.

In particular, these early studies show that high-antibody doses of convalescent plasma don’t trigger the immune system overreactions, called cytokine storms, that cause many of the most severe COVID-19 patients to die.

Both Wright and Casadevall attributed a lower death rate among hospitalized COVID-19 patients partly to improved therapies, including convalescent plasma.

These tests will be important because relying on COVID-19 survivors to produce convalescent plasma is too limited an approach in a pandemic, both because of the totally random batch of antibodies that each patient produces and the limited number of antibodies any one person can make.

In a second trial called ACTIV-3, 300 people hospitalized with mild to moderate COVID-19 will be given either the antibodies or a placebo infusion and watched for five days.