As the world searches for a Covid-19 panacea, treating patients with plasma taken from those who have recovered from the virus is presented as a possible remedy - but great challenges remain, scientists say.
It's been months since the new coronavirus started to rage across China, spreading to other countries and infecting more than a million people worldwide, but there is still no vaccine or clinically tested drug. However, a possible treatment that has existed for more than a century draws attention, with some scientists suggesting that it could be a game-changer - provided that certain flaws are removed.
What is this plasma treatment?
The approach revolves primarily around harvesting convalescent plasma, the yellowish liquid component of human blood, from a person who has 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 and neutralize parts of the virus. Remarkably, antibodies are produced against specific types of virus, becoming “Anti-virus serum”, Aleksey Kupryashov, head of blood transfusion at the Bakulev Cardiovascular Surgery Center, told RT.
In addition, plasma is more useful than blood itself “Because you don’t have to worry about blood type”, said Sergey Netesov, a leading virologist and member of the Russian Academy of Sciences.
The idea behind the therapy is very simple – sharing antibodies from patients with a strong immune system could help others, weaker ones, to recover.
Conceptualized by German physiologist Emil von Behring – the first Nobel Prize winner in medicine – the method has existed for over a century. Most recently, in mid-March, Arturo Casadevall of the Johns Hopkins School of Public Health and Liise-anne Pirofski of Albert Einstein Medical College defended the treatment, claiming that infusions of antibodies could potentially protect people from virus for several weeks.
Later in the same month, their Chinese colleagues suggested that convalescent plasma had helped Covid-19 patients even with ventilation, but their study was based on only five cases.
Is it effective or at least SAFE?
As health workers said in the Hippocratic Oath, doing no harm is the key to medicine. Can we be sure that treating Covid-19 patients with antibody-rich plasma will do no harm?
“We transfuse hundreds of thousands [or] millions of units of blood in hospitals, and the serious consequences are really small, ” Professor Jeff Bailey of US-based Brown University told RT. The logic behind the use of 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, a big problem is that “This is a new disease, we haven’t had a lot of transfusions. “
Another concern that may arise is that every 200 or 400 milliliters of transfused plasma increases the patient’s blood flow. It will not be a problem if the patient’s kidneys are working well, but if they do not, the volume could increase the fluid in their lungs, making the condition worse.
But will the therapy work for everyone, given that there are no convincing statistics showing whether plasma transfusion is effective against Covid-19?
“You have to try it, only experimentation can tell us yes or no,” Russian virologist Netesov argued. In any case, trying an experimental therapy is better than “Die on the spot without any medicine. “
Front-line physicians urgently need trials to explore the benefits of plasma therapy as new drugs are developed, Bailey agreed.
What you want to know is if it helps to survive [by] 50 percent and something else helps survival [by] 25 percent, you probably want to go with the one that is 50 percent.
Even if it helps, finding donors will be a problem
However, the hardest part here is finding and verifying the incredibly small number of donors, especially compared to over a million cases of coronavirus worldwide. In addition, plasma for Covid-19 patients must be free from other diseases, such as hepatitis or HIV / AIDS.
“In fact, up to 50% of donor blood is rejected in most countries,” Netesov revealed, citing the example of China – a pioneer in plasma therapy – where almost one in 10 potential donors suffered from hepatitis. Russia, for example, has only a small number of Covid-19 patients recovered, and perhaps only half of them could donate blood, limiting the pelvis to dozens, the scientist admitted.
“The number of patients is even greater than the number of patients recovered. As long as this situation persists, we have no one to collect this plasma, “ Kupryashov of the Bakulev Center agreed.
Finding the right plasma dosage is also crucial in the circumstances, as doctors need to know what concentration of antibodies is sufficient to help cope with the virus. In the long run, however, manufacturers will generally process the plasma, increasing the amount of antibodies and allowing doctors to use smaller doses, said Bailey.
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Who sees the promise in plasma therapy?
Health authorities around the world have high hopes for plasma therapy, rapidly deploying trials and authorizing it for compassionate use – allowing the prescription of unapproved treatments if a dying patient has no other options and if the potential benefits outweigh the risks.
In the United States, where the number of coronavirus cases has now exceeded 312,000, the Food and Drug Administration (FDA) has directed “A new national effort” to facilitate the use of plasma therapy. “There are some limited data to suggest that convalescent plasma and hyperimmune globulin may have benefits in Covid-19 disease,” indicates the agency.
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 on the NHS to urgently store antibody-rich plasma for such needs. France is also expected to start trials for the promising therapy next Tuesday.
Russia is also catching up with the trend. The country’s famous Sklifosovsky Institute for Emergency Care will be the first to try to infuse plasma in the coming days, local media reported. In addition, the Vector Institute – a leading research center in virology and biotechnology – has developed a test to measure antibodies in those who have survived Covid-19. The institution has previously examined blood samples from 11 people who have recovered from the virus, said Deputy Prime Minister Tatiana Golikova.
Iran, recently a coronavirus hotspot, will also follow, as does Turkey, where the Red Crescent chief insists he may become “One of the most effective applications in the world” against contagion.
At the moment, many other treatment options are being considered by the international health care community, ranging from antimalarial drugs to HIV drugs. A range of Covid-19 vaccines is also under development, although they appear to be months – if not years – from being put into use.
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