Around 500 people are to benefit from an experimental treatment for Covid-19 after 1,000 units of plasma were donated from recovered patients.
From Monday, between 11 and 14 hospitals will take part in the trial, with “many more” to follow as the collection programme expands, NHS Blood and Transplant (NHSBT) said.
It is hoped the treatment, known as convalescent plasma, will help patients whose bodies are not producing sufficient antibodies to fight the virus.
NHSBT said it is collecting up to 100 units of donated convalescent plasma a day, with 994 units received by Friday morning.
With each patient receiving two units each, it is hoped the donated plasma could help around 500 people.
The NHSBT said it is now able to collect convalescent plasma at all 23 of its permanent donor centres.
While transfusions have begun, the effectiveness of plasma treatment will not be known until the trial ends, with results expected in the late summer.
The health service is aiming to be in a position to roll out the treatment widely if it proves successful.
Nicola Green, 45, from Widnes, donated convalescent plasma at Liverpool Donor Centre on Friday.
She had spent two days in hospital with Covid-19 after experiencing a fever and severe headaches, followed by a cough and fatigue.
She said: “It’s amazing to feel I am helping because I wouldn’t want anyone to go through what I went through or even worse.”
Nearly 200 people have been recruited to collect the plasma, which will also be picked up from temporary donation spaces in six regional operations centres and three new community venues in London.
Professor David Roberts, NHSBT associate medical director for blood donation, said: “We thank everyone who is donating convalescent plasma.
“We know many people who can donate will have been through a difficult experience and we are grateful for their help in reaching this milestone.
“There is still much more to do. We can reassure people that convalescent plasma donation is safe and easy.
“You’ll also be taking part in groundbreaking research. If you get the call, please donate.”