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expert reaction to announcement that US will allow wider use of convalescent blood plasma treatment for COVID-19

It has been reported that the US will allow wider use of convalescent blood plasma treatment for COVID-19 patients. 


Prof Stephen Evans, Professor of Pharmacoepidemiology, London School of Hygiene & Tropical Medicine, said:

“A large observational study has appeared in preprint which followed those, hospitalised with COVID-19, who had been transfused with at least one unit of plasma from patients who had recovered from COVID-19. The level of anti-bodies in the plasma had not been checked prior to the transfusion being given.

“It was not a randomised study so there were no good comparisons with what would happen if they had not received the plasma. The observational nature of the study can introduce a lot of uncertainty around the strength of the conclusions.

“However, it is expected on the basis of previous experience with diseases like Lassa fever that plasma from those who have recovered from a disease will often help patients who receive the plasma to recover.

“In this study, those who were transfused 4 or more days after COVID-19 diagnosis had a mortality rate of about 12%; those who were transfused sooner after diagnosis had a mortality rate of about 9%.

“This suggests, but does not prove, that convalescent plasma can be helpful, especially given soon after diagnosis of COVID-19.

“Measuring the actual levels of antibody in the plasma afterwards, it was found that there was a trend to improved survival the higher the level of antibody in the transfused plasma. This is further evidence suggesting that the benefit is real, but the true magnitude of benefit will only be known when the results of randomised trials are completed and reported.

“Allowing the use of convalescent plasma seems reasonable, but it is a pity that randomised trials which would provide the best evidence are not conducted in much larger numbers of patients. Patients who have recovered should certainly be encouraged to donate blood if they can and for that to be used for high quality research.

“The risks of giving plasma are generally well-known so it is not a real question of safety that needs to be addressed, but of efficacy.”


Prof Martin Landray, Professor of Medicine & Epidemiology, Nuffield Department of Population Health, University of Oxford, said:

“Convalescent plasma is a treatment that shows huge promise. However, there is a huge gap between theory and proven benefit. That is why randomised clinical trials are so important. At present, we simply don’t know if it works.

“It is unfortunate that despite the scale of the epidemic in the United States and their rich history of rigorous clinical research, so many patients continue to be given an unproven treatment. If just a few thousand patients were to be randomised, we would have the answer. If effective, convalescent plasma could be rapidly used worldwide. If not, it could be abandoned.

“Here in the UK we have taken a different approach: the RECOVERY trial includes an assessment of convalescent plasma for patients hospitalised with COVID-19 and will provide the evidence needed to treat patients appropriately.

“There can be no short-cuts – a pandemic is no time for guesswork. We need reliable evidence to deliver the best patient care.”


Dr Stephen Griffin, Associate Professor in the School of Medicine, University of Leeds, said:

“Patient plasma has the potential to be an effective treatment for SARS-CoV-2 infection. However, in the absence of sufficiently powered, well-controlled trials, there is a risk that the implementation of its use may be less than optimal, resulting in patients not receiving the best possible care. Moreover, there is also the possibility that the treatment is in fact ineffective. This is particularly important given some of the uncertainty around the nature of patient immune responses to SARS-CoV-2 and how they relate to the eventual outcome in COVID-19.

“It is also profoundly unfortunate that the FDA appears to have been under a degree of political pressure to make this decision. It appears that the lessons from hydroxychloroquine have not been learned. The safety and efficacy of any medicine should be the subject of rigorous and constant review within a particular disease category.”


A spokesperson for NHS Blood and Transplant said:

“NHS Blood and Transplant is already collaborating with the wider NHS on world leading treatment trials of convalescent plasma.

“The observational studies coming from America are promising and support the need for people to continue to donate convalescent plasma in England. However, they are not conclusive.

“Randomised control trials are the gold standard for determining the effectiveness of a new treatment. The UK is leading the world in setting up randomised controlled trials for COVID-19 convalescent plasma.

“We need people who have recovered from COVID-19 to offer to donate convalescent plasma at”


All our previous output on this subject can be seen at this weblink:


Declared interests

Prof Stephen Evans: “No conflicts of interest. I am funded (1 day/week) by LSHTM. They get funding from various companies, including Astra Zeneca and GSK but I am not funded by them, I have no involvement in obtaining funding from them and I am not an investigator or any grants obtained from them. I am the statistician to the “meta-Data Safety and Monitoring Board” for CEPI. I will probably be paid for my attendance at meetings and expenses for travel.”

Prof Martin Landray: “Co-chief investigator of the RECOVERY trial of potential treatments for COVID-19 (funded by UKRI and NIHR). Research funding to University of Oxford received from Novartis, Boehringer Ingelheim, and Merck Sharp & Dohme. Infrastructure and core funding received from Health Data Research UK, NIHR Oxford Biomedical Research Centre, UK Biobank Ltd, MRC Population Health Research Unit, and British Heart Foundation Centre for Research Excellence. Employee of University of Oxford with salary supported by Li Ka Shing Foundation, Health Data Research UK, NIHR Oxford Biomedical Research Centre, Wellcome Trust, and National Health Service.”

Dr Stephen Griffin: “No conflicts of interest.”

None others received.

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