Injecting Covid-19 patients with the blood of survivors speeds up their recovery and reduces their symptoms, research suggests.
A scientific review claimed convalescent plasma therapy cleared the disease in less than a week in adults under the age of 60.
But the antibody-rich plasma took between 10 to 30 days to fend off the disease in elderly patients, who are prone to severe illness from Covid-19.
Scientists in Sweden and Finland, behind the study, said global research indicated the unproven therapy ‘is safe and effective’.
But none of the studies included in the review compared patients receiving plasma to a control group — considered the gold standard of scientific research.
Early results from the first randomised control study in China actually suggested the treatment makes no difference.
Hundreds of NHS patients are currently being treated with convalescent plasma as part of a trial at London’s Guy’s and St Thomas’ Hospital.
It’s thought that antibodies in recovered patients’ blood can bolster the struggling immune system of infected people.
Health Secretary Matt Hancock donated his blood after recovering from coronavirus in March
The treatment works using the liquid part of the blood, known as convalescent plasma (pictured, at the Amulfo Arias Madrid Hospital in Panama City)
The treatment — used for around a century for other infections — works using the liquid part of the blood, known as convalescent plasma.
This antibody-rich plasma is injected into Covid-19 patients struggling to produce their own antibodies, with hopes it can help clear the virus.
Donating takes around 45 minutes and medics filter the blood through a machine to remove the plasma, in a process known as plasmapheresis.
The treatment – used for around a century for other infections – works using the liquid part of the blood, known as convalescent plasma. The yellowy liquid is removed from former patients’ blood. Pictured, Dr Zhou Min shows his plasma after donating in Wuhan, China
A clinical trial of convalescent plasma on coronavirus patients is being conducted at St Thomas’ hospital. Pictured, Matt Hancock donating Covid-19 antibodies in London
Donors must have tested positive for the illness either at home or in hospital — but they should be three to four weeks into their recovery.
The promising treatment was used a century ago in the 1918 Spanish flu pandemic, which is estimated to have killed up to 50million people.
In the latest study, researchers from the Karolinska Institutet in Sweden and Institute for Health and Welfare in Finland reviewed 10 studies looking into CP therapy.
There were a total of 61 coronavirus patients involved in the trials, which took place in China, South Korea and the US. They were aged between 19 and 100.
Exactly half of the patients recovered within the first week and 40 per cent cleared the disease between eight and 29 days after CP transfusion. For the remaining patients, recovery data was unavailable.
The analysis — not yet published in a journal or scrutinised by other scientists — showed patients over the age of sixty took twice as long to recover than younger volunteers.
There were no noticeable differences in recovery time between genders, despite men being more likely to fall severely ill with the disease — or patients with and without underlying chronic diseases.
Writing in the study, the academics, led by Ville Pimenoff, of the Karolinska Institutet, said: ‘The results reviewed here suggest that CP therapy for COVID-19 is safe and effective…. and created an immediate recovery response in about half of the patients reviewed.
‘This signal of shorter time to recovery was significantly associated to patients under the age of sixty.’
The scientists acknowledged early results from China have indicated the therapy has no effect on coronavirus patients.
They added: ‘First randomized clinical trial results, however, revealed no improvements in recovery time for elderly patients with severe COVID-19 between standard treatment alone and added with convalescent plasma.
‘Accordingly, we argue that older patients may need a significantly longer time for recovery. Further randomized clinical trial data for COVID-19 with rigorous ethical standards is urgently needed.’
There is no cure for the killer coronavirus and thousands of patients worldwide are involved in trials of promising medicines.
A key advantage to the blood based therapy is that it’s available immediately and relies only drawing blood from a former patient.
It is also significantly cheaper than developing a new drug, which costs millions to take through trials and regulation before mass production.
Infusing patients with blood plasma has also been used to tackle SARS and MERS, two similar coronaviruses, as well as the deadly infection Ebola.
Plasma makes up around 55 per cent of all blood volume and provides the liquid for red and white blood cells to be carried around the body in.
By injecting this into patients it can provide their bodies with a vital dose of crucial substances called antibodies.
When someone contracts coronavirus, their immune system produces antibodies which attack the virus.
The antibodies build up over a month and are stored in the plasma, ready to be released if the virus enters their body again.
It is not clear how long antibodies last for, providing some form of protection, in people who have had SARS-CoV-2.
CP therapy may be the best hope for COVID-19 patients while scientists work to develop new, specific treatments for the disease.
A clinical trial of convalescent plasma on coronavirus patients is being conducted at St Thomas’ hospital.
The hospital says if the trials prove the treatment to be effective, NHS Blood and Transplant will begin a national programme to deliver up to 10,000 units of plasma per week to the NHS, enough to treat 5,000 patients each week.
The results are expected in a matter of weeks.
A Chinese study published in the Journal of the American Medical Association found CP therapy failed to make a difference in Covid-19 patients.
In a randomized trial involving 103 COVID-19 patients, convalescent plasma made no difference in the time it took to show signs of improvement or in rates of death at 28 days versus a placebo.
There were some potentially encouraging results among patients who were ‘severely ill’ but not sick enough to be in the intensive care unit.
They recovered roughly five days faster if they got the plasma treatment, and more of them improved within 28 days of starting treatment.
The study was somewhat hampered as researchers were not able to enroll as many patients as they had hoped because the epidemic started to come under control in their region, and it was stopped early.
Had they been able to enroll as many patients as originally planned, the results might have been different, they noted.