What is plasma? When people get sick, immune systems generate antibodies to fight the disease. Those antibodies (especially among very sick patients) float in people’s blood plasma — the liquid component of blood.
How can it be used? Plasma from a recovered person (who was very sick) can be injected into a currently sick person. The antibodies fight the virus early until the patient’s own immune system has enough to fight. Plasma has been used to fight epidemics, like the 1918 Spanish Flu, diphtheria epidemic in the 1920s, and the Ebola outbreak in 2014.
Plasma to fight COVID19? This has slowly come to the surface in the 2020. Here’s a timeline…
January 20-March 25: China treated 5 COVID19 patients with plasma. It worked.
March 24: FDA issued guidelines for using plasma in emergency investigations of new drug protocols (called eIND)
March 31: COVID19 plasma was used for the first time in the U.S. (Houston Methodist). It worked (for the most part).
May 14: A meta-analysis was published. Only 8 plasma studies had been conducted thus far and they were mainly “case studies” (basically a story with what happened with a few patients). There were no randomized control trials (RCT). The conclusion? We have no idea if plasma works because we don’t have enough evidence.
July 10: An updated meta-analysis was published pooling all studies on plasma. There were 20 published studies by now, but only 1 RCT. Their conclusion? We have no idea if plasma works because we don’t have enough evidence.
August 13: Mayo Clinic released a study with over 35,000 patients. They found that plasma helped with patient outcomes (like less death). BUT this was not peer-reviewed, which is important because this study has some serious limitations. Most importantly, there was no placebo group. The specific role of plasma is unclear because all patients received at least one additional medicine at the same time. This makes it difficult to know whether it was the plasma or the drug that helped the patients.
August 23: Nonetheless, the FDA allowed emergency authorization for doctors to treat Covid-19 using plasma
August 25: Three randomized control trials had concluded (one in China, Netherlands, and Iraq). The Chinese study was stopped early because they couldn’t get enough people to enroll. The Netherlands study was stopped early because most of the participants already had antibodies. The Iraq study was too small to see whether plasma helped.
Today: From my count, there are 98 ongoing studies evaluating plasma, of which 50 are randomized. We don’t have the results of these studies yet.
But… if it’s worked for other pandemics, why not just use plasma for everyone? Safety. 14 of the current 20 studies have reported serious adverse events with plasma. In one study, scientists reported that 4 deaths were directly linked to plasma infusion (out of 15 deaths total). It’s important we get this science right.
So, now what? We wait. We NEED rigorous studies to conclude. These are very difficult to conduct, though, because we need enough people to donate plasma AND we need enough people to agree to be infused. But, thanks to the perseverance of many scientists and brave community members, results should be coming out soon. TBD.
First plasma treatment in China: https://jamanetwork.com/journals/jama/fullarticle/2763983
Mayo clinic study: https://www.medrxiv.org/content/10.1101/2020.08.12.20169359v1
FDA August announcement: https://www.fda.gov/media/141480/download