Former coronavirus hospital patients are being urged to donate plasma as part of a major trial.
Research is being carried out to assess whether convalescent plasma donations can be transfused into patients who are struggling to develop their own immune response.
NHS Blood and Transplant (NHSBT), which is collecting the plasma for the trial, said people who were treated in hospital for COVID-19 produce the most antibodies, which makes them priority plasma donors.
The plasma from former patients is rich in the antibodies that develop as a person recovers from an illness.
It is then transfused into people who are seriously ill with COVID-19 and struggling to develop their own antibodies.
Being treated with convalescent plasma could become widespread practice in hospitals if the trial is a success.
More than three-quarters of COVID-19 patients had enough antibody levels for their donation to be used in the national trial.
Just 30% of coronavirus patients who did not need hospital treatment had high enough antibody levels.
Anyone who had COVID-19 is being urged to come forward and donate, including men who had the symptoms but no test.
So far, more than 13,000 donations have been taken, including more than 800 from former COVID-19 hospital patients.
Dr Lise Estcourt, head of NHSBT’s Clinical Trials Unit, said: “These figures demonstrate how important it is for people who were hospitalised with coronavirus to donate – they are most likely to be able to save the lives of others seriously ill people.
“These donors have higher antibody levels because while initially your immune system will try and fight off a virus with white blood cells, if you become more ill, your immune system needs to produce more antibodies that neutralise or kill the virus.”
People who have had coronavirus are being encouraged to donate by calling or 0300 123 23 23 or visiting the www.nhsbt.nhs.uk website.