Magic bullet for Covid-19? Scientists look to century-old plasma treatment, but there are some big ‘BUTS’
As the world seeks a Covid-19 panacea, treating patients with plasma harvested from those who have recovered from the virus is being touted as a possible cure – but big challenges still remain, scientists say.
It's been months since the novel coronavirus started to rage across China, spilling over to other countries and infecting more than a million people around the world, but there is still no clinically tested vaccine or medication. However, one possible treatment that has been around for over a century is attracting attention, with some scientists suggesting it could be a game-changer – provided that certain flaws are removed.
What is this 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 – 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," Aleksey Kupryashov, head of blood transfusion at Bakulev Center of Cardiovascular Surgery, explained to RT.
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 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 the Albert Einstein Medical College championed the treatment, claiming infusions of antibodies could potentially protect people from the virus for several weeks.
Later in the same month, their Chinese colleagues suggested that convalescent plasma had helped Covid-19 patients even on ventilation, but their study was based on only five cases.
Is it efficient or at least SAFE?
As health workers used to say in the Hippocratic Oath, doing no harm is key in medicine. Can we be sure that treating Covid-19 patients with antibody-packed plasma will do no harm?
"We transfuse hundreds of thousands [or] 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 explained. 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. This will present no problem if the patient's kidneys work well, but if they don't, the volume could increase fluid in their lungs, worsening the condition.
But will the therapy work for everyone, given that there are no compelling statistics showing whether the plasma transfusion is efficient against the Covid-19?
"You have to try it, only experimenting can tell us yes or no," argued Sergey Netesov, a leading virologist and member of the Russian Academy of Sciences.
At any rate, trying experimental therapy is better than "dying on the spot without any medication."
Physicians on the front line urgently need trials to study the benefits of plasma treatment as new drugs are being developed, Bailey agreed.
What you want to know is if this helps survival [by] 50 percent and something else helps survival [by] 25 percent, you probably want to go with the one that's 50 percent.
Dr Charles Rupprecht of the Department of Biomedical Sciences at Ross University said “there is no magic bullet” in the absence of peer-reviewed, large-scale, long-term, double-blinded studies proving the benefits of plasma in Covid-19 treatment.
The scientist, who leads the rabies section at his institution, referred to that disease as an example. Rabies immune globulin (RIG) – which also contains large amounts of antibodies from donated blood – is “one critical part of prevention after humans have been exposed to a rabid animal,” but it’s “short-acting” and is usually used in a healthy patient before “illness onset.”
Still, no specific coronavirus treatment has been proven to be effective, so doctors and patients need “the tincture of time," as there are always safety issues to consider in the use of human blood products, he cautioned.
Even IF it helps, finding donors will be a problem
However, the hardest part here is finding and vetting donors, the number of which is appallingly small, especially compared to more than one million coronavirus cases globally. Also, plasma intended for Covid-19 patients must be free from 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," Netesov revealed, citing the example of China – a pioneer in plasma treatment – where almost one-in-10 potential donors had hepatitis. Russia, for instance, has only a tiny number of recovered Covid-19 patients, 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 what 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 said.
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Health authorities around the world have high hopes for plasma treatment, rapidly rolling out trials and authorizing it for compassionate use – allowing unapproved treatments to be prescribed if a dying patient has no other options, and if the potential benefits outweigh the risks.
In the US, where the number of coronavirus cases has now exceeded 312,000, the Food and Drug Administration (FDA) has 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 states.
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 throughout the country.
In the UK, coronavirus patients are about to receive the experimental treatment, with experts calling on the NHS to urgently stockpile antibody-rich plasma for such needs. France is also set to start trials for 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 have reported. Additionally, the Vector Institute – a leading research center of virology and biotechnology – has developed a test for measuring antibodies in those who have survived Covid-19. The institution has already screened blood samples from 11 people who recovered from the virus, 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 could become "one of the world's most effective applications" against the contagion.
For the time being, many other treatment options are being considered by the international healthcare community, ranging from anti-malarial drugs to HIV medication. A range of Covid-19 vaccines are also being developed, although they seem to be months – if not years – away from being commissioned.
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