Men appear to produce higher levels of Covid-19 antibodies than women, figures suggest.
Covid-19 survivors are being sought to donate blood plasma as part of a major trial assessing whether it could help some of the sickest patients.
The trial is ongoing 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 new analysis had found that men produce more coronavirus antibodies than women, which makes them better plasma donors.
The new figures show that 43% of male donors had plasma rich enough in antibodies for their plasma to be included in the trial, compared with 29% of women.
Professor David Roberts, associate director for blood donation at NHS Blood and Transplant, said: “We’d still like to hear from anybody who had coronavirus or the symptoms. More plasma donors are needed.
“But we’d especially want to hear from men. We test every plasma donation and men have higher antibody levels, which means we’re more likely to be able to use their plasma to save lives.
“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.
“Our studies, and many others around the world, show men with Covid-19 are more likely to become seriously ill than women. This makes them better plasma donors once they have recovered.”
Last week it was announced that anyone who tests positive for Covid-19 through the national testing programme will be asked to join a blood plasma trial.
NHSBT said people confirmed with the virus through the “pillar 2” national testing programme will receive a text message 21 days after their result to see whether they are willing to donate plasma.
The texts will now be sent on a weekly basis to anyone who tests positive through the national testing programme. People will receive them 21 days after their result.
The plasma from former patients is rich in the antibodies that develop as a person recovers from an illness.
It is transfused into people who are seriously ill with Covid-19 and struggling to develop their own antibodies.
If the trial is successful, being treated with convalescent plasma could become a widespread practice in hospitals.
Two plasma donors have described their decision to donate as a “no-brainer”.
Simon Callon, 51, of St Helens, Merseyside, survived Covid-19 but lost his father Noel to the disease.
“I don’t want anybody going through what happened to my dad,” he said.
“He died on a hospital ward with no family or friends, with a nurse holding his hand. Only 10 people were allowed at his funeral.
“He’d had a fall at home but the paramedics found his oxygen levels were low and he had a high temperature so they took him in.
“He had been with my mum for more than 60 years. He was ex-RAF and a long distance lorry driver but also an amateur painter who taught classes. His students formed a socially-distanced guard of honour with their paintbrushes.
“To me, donating plasma was a no-brainer. If you can save somebody or help somebody, you would do it.
“The donation was easy, no pain. The staff were brilliant. I hope I can help someone.”
Dr Wassim Shamsuddin, a consultant anaesthetist at Milton Keynes University Hospital Foundation Trust, donated convalescent plasma at Oxford Donor Centre after recovering from Covid-19.
The 40-year-old, from Bicester, said: “I have seen the effects of the virus first-hand and how it has taken the lives of many people, both old and young.
“When the opportunity came to donate plasma and hopefully antibodies to help others in the fight against Covid-19, it was a no-brainer for me.
“I have seen how the virus has disproportionately affected the BAME group, within the healthcare professionals and in the community.
“If plasma turns out to be one of the treatments shown to be of benefit to individuals then I would have played my part.”
Anyone who has had coronavirus or the symptoms and is able to travel to a donor centre can offer to donate by calling 0300 123 2323 or visiting www.nhsbt.nhs.uk