A scientific trial has poured cold water on the hope that the blood plasma of recovered Covid-19 patients is an effective treatment for the disease.
Convalescent plasma had shown promise in early observational studies but a large-scale clinical trial has found it does not prevent death or severe symptoms.
Half were given plasma while the others were not, and the data reveals the much-heralded therapy did nothing to improve a patient’s prognosis.
Health Secretary Matt Hancock, who caught the coronavirus during the UK’s first wave at the start of the year, himself donated plasma and encouraged other recovered patients to do the same.
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Convalescent plasma had shown promise in some early observational studies but a large-scale clinical trial has found it to be ineffective.
Pictured, Health secretary Matt Hancock donating blood. He contracted the coronavirus earlier this year and encouraged other recovered patients to do the same thing to boost stores of convalescent plasma
It had been previously believed that blood plasma, a yellowish liquid in our blood which contains the antibodies to fight off viruses, could help treat Covid-19.
In August, US President Donald Trump announced the FDA has given an emergency use authorisation for convalescent plasma to be used as a Covid-19 treatment.
Other countries, including Britain, have been stockpiling blood plasma so the treatment could be rolled out if it proved effective.
According to a NHS Blood and Transplant spokesperson, the type of plasma collected in this study is inferior to that which is being gathered in the UK.
‘This was a trial which used donations with antibody levels around 6 to 10 times lower than we are using,’ they said.
‘There is other promising evidence that convalescent plasma transfusions with high antibody levels could improve patient outcomes.
‘We are carrying out two world leading full randomised control trials using only high antibody donations (we are only using donations with a EUROImmun score of 6 or greater), with several thousand patients, which should provide clear answers.’
The findings of the new study, led by Professor Aparna Mukherjee at the Indian Council of Medical Research and Dr Elizabeth Pathak at the Women’s Institute for Independent Social Enquiry, were published in The British Medical Journal (BMJ).
Professor Mukherjee said: ‘As a potential treatment for patients with moderate Covid-19, convalescent plasma showed limited effectiveness.
‘Future research could explore using only plasma with high levels of neutralising antibodies, to see if this might be more effective.’
The study tracked how patients responded to the treatments after one, three, five and seven days. They were also checked 14 and 28 days post treatment.
Medics in India enrolled 464 adults confirmed to be infected with the coronavirus and hospitalised by their symptoms between April and June. Half were given plasma while the others were not, and the data reveals the much-heralded therapy did nothing to improve a patient’s prognosis
Health Secretary Matt Hancock, who caught the coronavirus during the UK’s first wave at the start of the year, himself donated plasma earlier this year
At the four-week mark, 44 (19 per cent) of participants in the plasma group either died or their condition worsened and was classed as ‘severe disease’.
For the control cohort, only 41 people (18 per cent) died or deteriorated.
The researchers randomised the study to ensure the only difference between the two groups of people was whether or not they received the plasma of a recovered patient.
Dr Pathak said: ‘This rigorous trial shows that convalescent plasma is ineffective for Covid-19, and its implications should be carefully considered by both safety monitoring and institutional review boards.
There was no difference among patients who had received blood plasma with high levels of antibodies, the researchers also found.
Dr Pathak said: ‘As such, they say, in settings with limited laboratory capacity, convalescent plasma does not reduce 28 day mortality or progression to severe disease in patients admitted to hospital with moderate covid-19.’
However, blood plasma transfusions did improve patients shortness of breath and fatigue, the researchers found.
Prof Martin Landray, Professor of Medicine & Epidemiology, Nuffield Department of Population Health, University of Oxford and Co-lead, RECOVERY trial, says that while this study is the most comprehensive investigation into plasma treatment yet, much more work is needed to write it off completely.
‘Here in the UK, the RECOVERY trial is studying this important question at over 120 NHS hospitals across the country,’ he says.
‘The NHS Blood Transfusion Service is collecting convalescent plasma from people who have had coronavirus.
‘The convalescent plasma is then tested and those units with the highest levels of antibodies are then used as part of the trial.
‘Over 1900 patients have taken part in this particular part of the study so far and we continue to enrol patients in order to ensure that we get clear answers that will give doctors the information they need to treat future patients.
‘We anticipate answers will become available within the next few months.’
WHAT IS CONVALESCENT PLASMA AND WHERE HAS IT BEEN USED?
Convalescent plasma has been used to treat infections for at least a century, dating back to the 1918 Spanish flu pandemic.
It was also trialed during the 2009-2010 H1N1 influenza virus pandemic, 2003 SARS epidemic, and the 2012 MERS epidemic.
Convalescent plasma was used as a last resort to improve the survival rate of patients with SARS whose condition continued to deteriorate.
It has been proven ‘effective and life-saving’ against other infections, such as rabies and diphtheria, said Dr Mike Ryan, of the World Health Organization.
‘It is a very important area to pursue,’ Dr Ryan said.
Although promising, convalescent plasma has not been shown to be effective in every disease studied, the FDA say.
Is it already being used for COVID-19 patients?
Before it can be routinely given to patients with COVID-19, it is important to determine whether it is safe and effective through clinical trials.
The FDA said it was ‘facilitating access’ for the treatment to be used on patients with serious or immediately life-threatening COVID-19 infections’.
It came after New York Governor Andrew Cuomo said that plasma would be tested there to treat the sickest of the state’s coronavirus patients.
COVID-19 patients in Beijing, Wuhan and Shanghai are being treated with this method, authorities report.
Lu Hongzhou, professor and co-director of the Shanghai Public Health Clinical Centre, said in February the hospital had set up a special clinic to administer plasma therapy and was selecting patients who were willing to donate.
‘We are positive that this method can be very effective in our patients,’ he said.
Meanwhile, the head of a Wuhan hospital said plasma infusions from recovered patients had shown some encouraging preliminary results.
The MHRA has approved the use of the therapy in the UK, but it has not been revealed which hospitals have already tried it.
How does it work?
Blood banks take plasma donations much like they take donations of whole blood; regular plasma is used in hospitals and emergency rooms every day.
If someone’s donating only plasma, their blood is drawn through a tube, the plasma is separated and the rest infused back into the donor’s body.
Then that plasma is tested and purified to be sure it doesn’t harbor any blood-borne viruses and is safe to use.
For COVID-19 research, people who have recovered from the coronavirus would be donating.
Scientists would measure how many antibodies are in a unit of donated plasma – tests just now being developed that aren’t available to the general public – as they figure out what’s a good dose, and how often a survivor could donate.
There is also the possibility that asymptomatic patients – those who never showed symptoms or became unwell – would be able to donate. But these ‘silent carriers’ would need to be found via testing first.
Japanese pharmaceutical company Takeda is working on a drug that contains recovered patients antibodies in a pill form, Stat News reported.
Could it work as a vaccine?
While scientists race to develop a COVID-19 vaccine, blood plasma therapy could provide temporary protection for the most vulnerable in a similar fashion.
A vaccine trains people’s immune systems to make their own antibodies against a target germ. The plasma infusion approach would give people a temporary shot of someone else’s antibodies that are short-lived and require repeated doses.
If US regulator the FDA agrees, a second study would give antibody-rich plasma infusions to certain people at high risk from repeated exposures to COVID-19, such as hospital workers or first responders, said Dr Liise-anne Pirofski of New York’s Montefiore Health System and Albert Einstein College of Medicine.
That also might include nursing homes when a resident becomes ill, in hopes of giving the other people in the home some protection, she said.
Source: Daily Mail