It's testing existing treatments that may help people hospitalised with Covid-19.
The randomly-selected patient, who's under 18, is the first to be transfused with Covid-19 convalescent plasma through the recovery trial, according to NHS Blood and Transplant (NHSBT).
Although patients have already received plasma through the REMAP-CAP trial, this was not focused solely on coronavirus and only adults in intensive care were able to receive the treatment, according to NHSBT.
Convalescent plasma from former Covid-19 patients is rich in the antibodies that develop as a person recovers from an illness.
If the trial is successful, being treated with convalescent plasma could become a widespread practice in hospitals for those who are seriously ill and struggling to develop their own antibodies.
Selected hospitals are currently able to randomise patients to receive plasma in the recovery trial, which is open to patients of all ages admitted to hospital and being coordinated by the University of Oxford.
Plasma donations are being collected by NHSBT at all 23 of its donor centres in England - including in Oxford. As of June 1, some 263 units have been issued to hospitals, while a further 267 units are ready for issue.
The transfusion took place at the Royal Manchester Children's Hospital.
Dr Lise Estcourt, head of NHSBT's Clinical Trials Unit, said: "This is a welcome milestone and we expect the number of people receiving convalescent plasma transfusions within the trials will now grow.
"We can only provide convalescent plasma thanks to the generosity of people who donate after recovering from the illness.
"Please help the NHS find out whether this is an effective treatment for Covid-19 by donating plasma."
NHSBT is appealing for people who have recovered from Covid-19 or the symptoms, and who live near one of its 23 donor centres, to offer to donate their plasma by calling 0300 123 23 23 or visiting www.nhsbt.nhs.uk