Fast facts about COVID-19 convalescent blood plasma
President Donald Trump told the American people this week that convalescent plasma is a potential new treatment for COVID-19. His announcement followed the Food and Drug Administration’s decision Sunday to grant fast-track authorization for its emergency use as a treatment for hospitalized COVID patients.
This “emergency use authorization” triggered an outcry from scientists and doctors, who said the decision was not supported by adequate clinical evidence and criticized the FDA for what many perceived as bowing to political pressure.
Convalescent plasma contains antibodies against disease. Donations are being promoted as a potential COVID-19 treatment.
“Convalescent” refers to recovery from a disease. And plasma is the yellowish, liquid part of blood in which blood cells are suspended.
When someone is infected with a virus, the body generates antibodies to fight off the viral particles. Enter COVID-19. If an individual who has recovered from this virus donates their plasma, scientists can isolate the antibodies from the plasma and give it to patients who are still in the early stages of their COVID-19 infection. This infusion, in theory, should help people fight off the virus while their own body catches up and makes its own supply of antibodies.
It’s not a new concept. An infusion of antibodies via plasma has been used as a treatment for other types of diseases, such as rabies.
An FDA emergency use authorization allows companies and medical providers to deploy unapproved treatments or medical products in a crisis. The FDA said health care providers would be authorized to distribute COVID19 convalescent plasma to treat suspected or confirmed patients with COVID-19 while in the hospital.
Before the authorization, some top researchers and clinicians at the National Institutes of Health felt there was not sufficient scientific evidence to support pushing the treatment forward.
“A randomized placebo control trial is the gold standard,” said Dr. Howard Koh, who was an assistant secretary at the Department of Health and Human Services from 2009 to 2014 under President Barack Obama. “If you don’t have that standard and don’t have some evidence from a high-quality study or (a randomized controlled trial), you are left with suboptimal science and treatments in the long run that may not prove to work.”
Koh also said that for other COVID-19 treatments including the medication remdesivir, a randomized clinical trial had been done before the FDA OK’d it for emergency use.
When the emergency authorization for convalescent plasma was announced, HHS officials pointed to findings from a Mayo Clinic preliminary analysis as the rationale. The analysis has not been reviewed by other scientists and doctors.
The Mayo Clinic analyzed outcomes of patients who were given a low dose of plasma and those given a high dose. Those who got the high dose had a lower seven-day mortality rate (8.9%) compared with the seven-day mortality rate of those given a low dose (13.7%).
Critics of the convalescent plasma treatment say there must be randomized clinical trials to prove its effectiveness.