Researchers have discovered how to identify immunosuppressed people least likely to have COVID-19 antibodies, and suggested their findings might inform bespoke booster schedules for this population.
Additional COVID-19 vaccine booster doses and treatments are offered to immunosuppressed people to protect against severe COVID-19.
Dr Michelle Willicombe, a senior reader in renal pathology in the Department of Immunology and inflammation at Imperial College London (ICL), and study leader, said: "We know from previous research that people who have a weakened immune system were more likely to catch COVID-19. They were also more likely to need to go into hospital for treatment or die from COVID-19. Clinically vulnerable patients who are at increased risk are encouraged to attend if they are invited for a booster vaccine, in order to get the best protection against COVID-19."
However, how best to choose the individuals that receive these vaccine booster doses and treatments remained "unclear", the authors of a new study alerted.
Researchers from ICL, the universities of Southampton, Nottingham, and Cambridge, Nottingham University Hospitals NHS Trust, NHS Blood and Transplant, the National Disease Registration Service at NHS England, and IPSOS MORI, set out to investigate the association between seropositivity to SARS-CoV-2 spike protein with demographic, disease, and treatment-related characteristics after at least three COVID-19 vaccines in three cohorts of people who were immunosuppressed.
Using UK national disease registries, the cross-sectional study recruited 28,411 recipients of solid organ transplants, patients with rare autoimmune rheumatic diseases, and individuals with lymphoid malignancies, who were 18 years or older, resident in the UK, and who had received at least three doses of a COVID-19 vaccine.
Participants received a lateral flow immunoassay test for SARS-CoV-2 spike antibodies to complete at home, and an online questionnaire.
The median age of participants with solid organ transplants was 60 years, with rare autoimmune rheumatic diseases was 65 years, and with lymphoid malignancy was 69 years. Of the total cohort, 45.5% of participants were men, 54.4% women, and 94% were of White ethnicity.
One in Five Didn't Have Antibodies After COVID-19 Vaccination
The study, published in The Lancet Rheumatology, found that 77% of people who had a solid organ transplant, 79% of those with a blood cancer, and 86% with rare autoimmune disease, had antibodies after COVID-19 vaccination.
"Around one in five people with solid organ transplant, rare autoimmune disease, or lymphoid malignancies had no COVID-19 antibodies after three or more vaccinations," alerted the authors. They pointed out that "this proportion decreases with sequential booster doses".
This meant that people with compromised immune systems were less likely to have COVID-19 antibodies, "making them more vulnerable to a severe infection", underlined the authors.
The researchers also found that having more vaccinations (e.g. five vs three), being younger, and having previously had COVID-19, was associated with the presence of antibodies. Some medications that weaken the immune system reduced the likelihood of having antibodies, the authors pointed out.
Bespoke Booster Vaccination Schedules
Home antibody tests for at-risk groups could be used to target booster jabs and other preventative treatments, proposed the authors, who added that their study findings would help to "better plan care and treatment" for people living with these conditions.
"People who are less likely to have COVID-19 antibodies could be offered antibody testing and targeted interventions, such as further vaccine doses or preventative medicine," they suggested, adding: "The absence of antibodies could also influence which immunotherapy medications are given to those with different underlying conditions.".
Sean Lim, professor of haematology at the University of Southampton, and study co-author, suggested that in the future, home antibody tests could be offered to those "who we know are least likely to have antibodies" and that these people could be provided with "quick access to preventative treatments".
The authors concluded that it was possible to "find, identify, invite, and test" cohorts of people who are immunosuppressed. The findings could also help to develop "bespoke booster vaccination schedules" for different groups, Professor Lim suggested.
Dr Peter Lanyon, a consultant rheumatologist at Nottingham University Hospitals NHS Trust, and rare diseases clinical lead at the National Disease Registration Service, NHS England, said: "This study demonstrates the utility of national rare disease registration to identify and invite whole population-based cohorts of people to participate in research that answers important clinical questions and can inform clinical practice and health policy."
The study was funded by UK Research and Innovation, Kidney Research UK, Blood Cancer UK, Vasculitis UK, and the Cystic Fibrosis Trust.