As the world quests for Covid-19 panacea, treating actual patients with plasma harvested from those who recovered is touted as a promising cure for the fatal disease — but it still comes with big challenges, scientists say.
It’s been months since the novel coronavirus started to rage across China, spilling over to other countries and infecting over a million people around the world, but there is no clinically tested vaccine or medication to date. However, one method that has been around for over a century is turning heads, with some scientists suggesting it could become a game-changer — provided that certain flaws are removed.
What is plasma treatment about?
The approach basically revolves around harvesting convalescent plasma, the yellowish liquid component of human blood — from someone who recovered from a viral infection and transfusing it to a newly infected patient.
Plasma is essential here because it is rich in antibodies, namely proteins, that bind to parts of the virus and neutralize it. Remarkably, antibodies are produced against specific types of viruses, effectively becoming an “anti-virus serum,” Alexey Kupryashov, head of blood transfusion at Bakulev Center of Cardiovascular Surgery, explained to RT.
Moreover, plasma is more useful than blood itself “because you don’t have to take care about the blood type,” explained Sergey Netyosov, a leading virologist and member of Russian Academy of Sciences.
Now, the idea behind the therapy is very straightforward — sharing antibodies taken from patients with a robust immune system could help other, weaker ones, to recover.
Conceptualized by German physiologist Emil von Behring — the first recipient of the Nobel Prize in medicine — the treatment method has actually been around for over a century. Just recently, in mid-March, Arturo Casadevall of the Johns Hopkins School of Public Health and Liise-anne Pirofski of Albert Einstein Medical College championed the method, claiming infusions of antibodies could potentially protect people from the virus for several weeks.
Later in the month, their Chinese colleagues suggested that convalescent plasma helped Covid-19 patients even on ventilation, but their study was based on only five cases.
As health workers used to say in the Hippocratic Oath, doing no harm is key in any medication. Will it be the case in treating Covid patients with antibody-packed plasma?
“We transfuse hundreds of thousands of millions of blood units in hospitals and the severe outcomes are really low,” Professor Jeff Bailey of the US-based Brown University told RT. The logic behind using plasma against Covid-19 is “very strong” because “a person who has recovered has good antibodies that will block and neutralize the virus,” he reminded. However, one big issue is that “it’s a new disease, we haven’t transfused a lot.”
Another concern that may arise is that every 200 or 400 milliliters of transfused plasma expands the patient’s blood stream. There will be no problem if their kidney’s work well, but if they don’t, the volume can increase fluid in the lungs, worsening the patient’s condition.
But will the therapy work for everyone, given that there is no compelling statistics showing whether the plasma transfusion is efficient against the Covid-19?
“You have to try it, only experiment could tell yes or no,” Russia’s virologist Netyosov argued. At any rate, trying experimental therapy is better than “dying at the spot without any medication.”
Physicians on the frontline urgently need trials to know benefits of plasma treatment as new drugs are coming along, Bailey agreed.
What you want to know is if this helps survival 50 percent and something else helps survival 25 percent, you probably want to go with the one that’s 50 percent.
Even IF it helps, donors are the problem
However, the hardest part here is finding and vetting donors whose number is appallingly small, as opposed to over one million of coronavirus cases globally. Also, plasma intended for Covid patients must be free of other diseases, such as hepatitis or HIV/AIDS.
“As a matter of fact, up to 50 percent of donor blood is being rejected in most countries,” Netyosov revealed, citing example of China — a pioneer in plasma treatment — where almost every tenth potential donor had hepatitis. Russia, for instance, has only a tiny number of those who recovered, and maybe only half of them could donate blood, limiting the pool to mere dozens, the scientist acknowledged.
“The number of patients is still larger than the number of the recovered. As long as this situation persists, we have nobody to take that plasma from,” Kupryashov of the Bakulev Center agreed.
Finding the right dosage of plasma is equally crucial under the circumstances because doctors have to know which concentration of antibodies is enough to help cope with the virus. In the long run, however, manufacturers will usually process plasma, increasing the amount of antibodies and allowing doctors to use smaller doses, Bailey offered.
Health authorities around the world set their hopes high for plasma treatment, rapidly rolling out trials and authorising the compassionate use of it — a way which allows for prescription of unapproved drugs if a dying patient has no other options, and if potential benefits outweigh the risks.
In the US, where the number of Covid cases is now above 312,000, Food and Drug Administration (FDA) spearheaded “a new national effort” to facilitate the use of plasma treatment. “There are some limited data to suggest that convalescent plasma and hyperimmune globulin may have benefit in the Covid-19 illness,” the agency believes.
The Mayo Clinic will serve as the lead institution for the program, while the American Red Cross will collect plasma and distribute it to hospitals across the country.
In the UK, coronavirus patients are about to receive the experimental treatment, with experts calling NHS to urgently stockpiling antibody-rich plasma for such needs. France is set to start trials of the promising therapy next Tuesday.
Russia, too, is catching up with the trend. The country’s famed Sklifosovsky Institute of Emergency Care will be the first to try infusing plasma in the coming days, local media report. Additionally, the Vector Institute — a leading research center of virology and biotechnology — has developed a test measuring antibodies in those who defeated Covid. The institution has already screened blood samples from 11 people who recovered from Covid-19, Deputy Prime Minister Tatiana Golikova said.
Iran, recently a coronavirus hotspot, will also follow suit, as will Turkey, where the head of the Red Crescent insists that it would become “one of the world’s most effective applications” against the contagion.
For the time being, many other treatment options are being considered by international healthcare community, ranging from anti-malaria drugs to HIV medication. A range of Covid-19 vaccines are also being developed, although their commissioning seems to be months — if not years — away.
