The NHS is urgently appealing for more men who have had coronavirus to donate blood plasma because they make better donors than women.
Men are far more likely to donate a unit of plasma with a high level of antibodies, NHSBT said.
Since the convalescent plasma programme started, 73,369 women have offered to donate (63 per cent of all volunteers) through the NHS Blood and Transplant (NHSBT) website, much higher than the number of men – 42,809 (37 per cent of all volunteers).
Read more about treating COVID-19 with blood plasma:
A man booked in to donate for the first time is three times more likely to give a high antibody unit of plasma than a woman.
This is partly because men are more seriously affected by COVID-19 and produce more antibodies.
But it is also due to men being more likely to have large enough blood volumes and veins to meet the donation criteria.
The antibody-rich plasma can be transfused into people who are struggling to develop their own immune response, and the antibodies could slow or stop the virus spreading.
NHSBT is taking plasma donations for its collaborations with the Recovery and Remap-Cap platform trials, with donations urgently sought ahead of any second wave this autumn.
There is said to be promising evidence for the effectiveness of convalescent plasma but patient benefit needs to be demonstrated in randomised control trials.
Read more about COVID-19 trials:
Dr Lise Estcourt, head of NHS Blood and Transplant’s clinical trials unit, said: “We’re not sure yet why there is an imbalance in people coming forward but we do know we need more men to offer to donate.
“Men have a special role to play in fighting this virus. Men who’ve had coronavirus are more likely to be able to save lives.
“We’re urgently asking men who’ve had confirmed coronavirus or the symptoms to offer to donate and help us be prepared for any second wave of COVID this autumn – you could save lives.”
How do scientists develop vaccines for new viruses?
Vaccines work by fooling our bodies into thinking that we’ve been infected by a virus. Our body mounts an immune response, and builds a memory of that virus which will enable us to fight it in the future.
Viruses and the immune system interact in complex ways, so there are many different approaches to developing an effective vaccine. The two most common types are inactivated vaccines (which use harmless viruses that have been ‘killed’, but which still activate the immune system), and attenuated vaccines (which use live viruses that have been modified so that they trigger an immune response without causing us harm).
A more recent development is recombinant vaccines, which involve genetically engineering a less harmful virus so that it includes a small part of the target virus. Our body launches an immune response to the carrier virus, but also to the target virus.
Over the past few years, this approach has been used to develop a vaccine (called rVSV-ZEBOV) against the Ebola virus. It consists of a vesicular stomatitis animal virus (which causes flu-like symptoms in humans), engineered to have an outer protein of the Zaire strain of Ebola.
Vaccines go through a huge amount of testing to check that they are safe and effective, whether there are any side effects, and what dosage levels are suitable. It usually takes years before a vaccine is commercially available.
Sometimes this is too long, and the new Ebola vaccine is being administered under ‘compassionate use’ terms: it has yet to complete all its formal testing and paperwork, but has been shown to be safe and effective. Something similar may be possible if one of the many groups around the world working on a vaccine for the new strain of coronavirus (SARS-CoV-2) is successful.