Earlier this year, bags of blood that was claimed to be from recovered COVID-19 patients went on sale on the black market. It was marketed as a source of “life long immunity” from the virus.
Those sales are, obviously, dodgy. But harvesting someone’s blood for its ability to fight coronavirus and then injecting it into another? Well, that’s happening across the world.
So how much hope can we have in blood?
This week on The Case we’re looking at the three things we need to try and understand when it comes to using blood from recovered COVID-19 patients as a treatment for coronavirus; how it works, whether it will be effective against COVID-19 and if it is, would we still need a vaccine.
How does it work?
The very first Nobel Prize for Medicine in 1901 was awarded to Emil von Behring. He injected a toxin into horses, which made them produce antibodies in their blood to fight diphtheria disease -- a serious infection of the nose and throat. He then took that blood, purified it and transferred it into humans to prevent and cure the deadly infection.
Blood transfusion was also used to fight the Spanish Flu pandemic in 1918, Scarlet Fever in the 1920s and even today it’s especially useful for people who can’t be vaccinated against chickenpox or measles... and now it’s being used to fight COVID-19, as we wait for a vaccine.
But if you’ve recovered from COVID-19, your body has developed natural defences against it -- and those defences are in your blood. They’re the antibodies; they recognise foreign, dangerous intruders in your body (like infections) and they live in your plasma. (Which, if you didn't already know, is actually yellow.)
The idea is that you donate your plasma at a regular blood bank and it gets transferred to someone with COVID-19, sharing your body’s defences with them.
It’s actually kind of lovely.
The words you’ll hear being thrown around today are “convalescent plasma,” which roughly translates to ‘plasma of a recovered person’.
“The aim of the treatment is to help patients recover faster from the infection,” Associate Professor Zoe McQuilten, a hematologist from Monash University, told The Feed.
Seems pretty straight forward, right?
But will it be effective against COVID-19?
In the US, more than 20,000 coronavirus patients have received convalescent plasma. But that was part of an emergency access program to experimental treatment, not a clinical trial setting, which means convalescent plasma was measured for its safety, but not its effectiveness.
Lifeblood Australia is helping Australia go one step further. It’s been collecting plasma from recovered patients since May 2020. Three clinical trials are now underway here:
The first gives the plasma to COVID patients in hospital and the second to more severe patients in intensive care. The third takes a bunch of different people’s plasma, extracts the antibodies and mixes them into a kind of concentrated, “hyperimmune” cocktail.
Associate Professor Zoe McQuilten is leading the two hospital trials. She’ll be looking for evidence of fewer deaths as well as fewer and shorter ICU stays.
“If that looks like that is much lower in the group that receives convalescent plasma then we would determine [the treatment] is effective.”
But unlike a drug, whose ingredients can be measured and controlled, antibody levels vary from donor to donor, which means effectiveness could also vary from recipient to recipient.
“We will look at patients who will receive higher amounts of antibody...that will tell us if there’s an effect based on the volume of antibody administered,” Professor McQuilten said.
“Whether patients would benefit from repeated doses, we don’t know. That might be a subsequent study depending on what the initial trials find both here in Australia and internationally.”
And if these treatments work, would we still need a vaccine?
Short answer: yes.
A vaccine carries a part of the actual virus that wakes up your immune system, makes it ring the alarm bells and then creates its own antibodies against the intruder. That’s called “active immunity.” A plasma transfusion is “passive.” That means the body isn't creating its own antibodies - it’s borrowing them from someone else.
The catch is with borrowed antibodies: “it wouldn't be lasting immunity, it would be short term,” according to Professor McQuilten.
For lifelong immunity, we need an effective vaccine.
The Verdict
To lend immunity using plasma, people still need to get infected with COVID-19 first. So it’s feasible for countries like Brazil or the U.S. where cases reach into the millions, but maybe not for other nations… like Australia.
Until a vaccine arrives, the convalescent plasma treatment could still prove to be the difference between life and death. And for that, it’s worth exploring.
For more information on how to donate visit: https://www.lifeblood.com.au/convalescent-plasma or call Australian Red Cross Lifeblood on 13 14 95 and mention 'convalescent plasma studies'.
