Study into whether vaccination of previously infected generates stronger, broader coronavirus antibody response

24 May 2021

NHS Blood and Transplant (NHSBT) is carrying out a study in the Birmingham region aimed at confirming whether vaccination creates a huge increase in antibody levels in people who have already had coronavirus. 

Based on two small previous studies (1) (2), researchers believe it will generate antibody levels around 100-200 times higher than in people who have not had the virus.

The study will provide data for research into antibody therapies that can fight multiple viral strains. 

Previous research appears to show that exposure to both the virus and the vaccine could lead to a stronger, more broadly effective response against different types of the virus.

The NHSBT study, called C-Velvet, involves going back to 100 people who donated convalescent plasma after recovering from COVID. They are now being contacted by NHSBT and asked to give blood samples 28 days after their vaccination (3), at the blood and plasma donor centre in Birmingham New Street. The neutralising antibody levels will be compared against the antibody level from when they came as plasma donors.

Around 50 people have given samples so far.

Dr Lise Estcourt, Head of NHSBT’s Clinical Trials Unit, who is the study lead, said: “Previous small studies show people who’ve already had coronavirus generate a significantly higher antibody response to the vaccine – around 100 times higher or more.

“They also found an increase in the cross reactivity of the antibodies against different viral strains.

“Our C-Velvet study could have two benefits for potential treatments.

“We may identify plasma ‘super donors’ who provide the very high antibody levels needed for any trial of hyperimmune plasma.

“Secondly, our study could inform the development of monoclonal antibody therapies which react against more viral variants.”

Minister for Innovation Lord Bethell said: “The UK is home to a thriving industry for life sciences, research and development and the launch of the C-Velvet study will be an important addition to our immense quota of UK-based COVID-19 studies.

“These potential “super donors” could be invaluable for future COVID-19 treatments and trials to fight the virus and keep people safe.

“I look forward to seeing what this study will bring to bolster our fast-growing knowledge of the virus and its weaknesses so we can all build back better.”


  1. First related study: Antibodies elicited by SARS-CoV-2 infection and boosted by vaccination neutralize an emerging variant and SARS-CoV-1  
  2. Second related study: Antibody response to first BNT162b2 dose in previously SARS-CoV-2-infected individuals
  3. People are being asked to give samples, not blood donations.