Hospitals in England will increase the number of people getting blood plasma transfusions from recovered Covid-19 patients this week, to learn whether the antibody-rich serum can help combat the disease.
So far few severely ill patients in UK intensive care units have been treated with convalescent plasma, but the transfusions are thought to be more effective if used earlier on before the coronavirus causes devastating damage.
The NHS Blood and Transplant service (NHSBT) said its clinical trial unit had this week begun collaborating with the Oxford-led Recovery trial with the aim of getting convalescent plasma into thousands of people in hospital with coronavirus in England.
Under the trial all patients in hospital with Covid-19, rather than only those in intensive care, will be eligible for a serum transfusion provided they have no medical conditions or allergies to blood products that could put them at risk.
NHSBT has issued hospitals with 154 units of plasma from recovered patients but is actively seeking donors to provide more. Nearly 300 further units have been blood typed and screened for viruses to ensure they are safe to use. More than 1,500 are awaiting approval before they too are sent to hospitals.
Doctors at Guys and St Thomas hospital, in London, have administered convalescent plasma to one severely ill patient as part of a second trial NHSBT is working with, named Remap-Cap.
Before the plasma is used scientists run tests on the fluid to make sure it contains high levels of antibodies. If the levels are too low the antibodies will not be able to overcome the virus and could make infections worse.
Medical interest in convalescent plasma dates back to before the 1918 flu pandemic. The principle behind the therapy is that people who fight off severe infections tend to develop high levels of antibodies in their blood, which protect them in the future. Transfusions of donated plasma should boost the immune defences of newly infected patients. The therapy, therefore, could be particularly valuable in older patients or those with compromised immune systems.
Scientists suspect that people who fall severely ill with Covid-19 produce the strongest immune responses to the virus. But without trials it is unclear how effective the transfusions will be. Ideally, the serum would be given to patients as soon as they fall ill so the antibodies can attack the virus while it is still replicating and before it has the chance to cause massive lung damage.
A spokesperson for NHSBT said that over the summer a significant number of Covid-19 patients were expected who could receive convalescent plasma. Donations not used in the first wave of infections can be frozen and stored for potential use in any second wave in the autumn.
Prof Dave Roberts, associate medical director at NHSBT, and one of the trials principal investigators, said: “We are investigating whether this plasma can improve survival, and reduce ventilation and intensive care unit stay in Covid-19 patients. This is an exciting development as there is no proven treatment for Covid-19.
“Although there is some past evidence of patient benefit from the use of convalescent plasma, the safety and effectiveness of convalescent plasma transfusions needs to be confirmed by a robust clinical trial.”
There have been similar trials in China, the US and other countries, where tentative reports on small numbers of patients suggest the therapy helps Covid-19 patients.
The latest results from a trial at Mount Sinai hospital in New York City found that patients who received plasma were more likely to survive, and that those treated before being put on a mechanical ventilator in intensive care appeared to benefit most.
“Wed like people who have recovered from Covid-19, and who live near our 23 donor centres, to offer to donate by visiting www.nhsbt.nhs.uk or calling us on 0300 123 23 23. We especially want to hear from men, the over-35s, and all people who needed hospital treatment, as their plasma is likely to have the highest antibody levels.”