A NEW UK study has highlighted the critical role of detectable anti-SARS-CoV-2 antibodies in reducing the risk of COVID-19 infection and severe outcomes in immunosuppressed individuals. The study, which tracked 21,575 participants with conditions such as solid organ transplants (SOTs), rare autoimmune rheumatic diseases (RAIRDs), and lymphoid malignancies, aimed to investigate whether the absence of these antibodies after three or more COVID-19 vaccinations could indicate a higher risk for infection.
Between December 2021 and June 2022, participants were tested for anti-SARS-CoV-2 spike protein IgG antibodies and followed up for six months using linked National Health Service data. The study found that 18.5% of participants contracted COVID-19, with 556 needing hospitalisation and 17 dying within 28 days of infection. Notably, those who had detectable anti-SARS-CoV-2 antibodies were significantly less likely to contract the virus. Rates of infection varied by sociodemographic and clinical characteristics but, in adjusted analysis, having detectable anti-S Ab was independently associated with a reduced incidence of infection, with incident rate ratios (IRRs) of 0·69 (95% CI: 0·65–0·73) in the SOT cohort, 0·57 (CI: 0·49–0·67) in the RAIRD cohort, and 0·62 (CI: 0·54–0·71) in the lymphoid malignancy cohort.
Researchers emphasised the importance of ongoing COVID-19 protection strategies for immunosuppressed individuals, including the use of antibody testing to better tailor vaccination and therapeutic approaches. The study suggests that monitoring antibody responses could serve as an effective method for identifying those most at risk, ensuring timely interventions for vulnerable populations.
Helena Bradbury, EMJ
Reference
Mumford L et al. Impact of SARS-CoV-2 spike antibody positivity on infection and hospitalisation rates in immunosuppressed populations during the omicron period: the MELODY study. Lancet. 2025;405(10475):314-28.
