Humoral and cellular response to COVID-19 vaccination in patients with autoimmune inflammatory rheumatic diseases under real-life conditions

<jats:title>Abstract</jats:title> <jats:sec> <jats:title>Objectives</jats:title> <jats:p>Successful vaccination is key to overcoming the COVID-19 pandemic. Immunosuppressive medication is known to potentially compromise vaccination responses, and expansion of our knowledge on vaccination efficacy in patients with autoimmune inflammatory rheumatic diseases (AIIRD) is therefore of utmost importance.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>We conducted a single-centre observational study and evaluated the efficacy of approved COVID-19 vaccines in 303 adult AIIRD patients. Serum levels of IgG antibodies against the S1 subunit of SARS-CoV-2 spike proteins (anti-S IgG) were measured at least two weeks after vaccination. In a subgroup of patients without humoral response, T-cell responses were determined using an interferon-γ gamma release assay.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Overall seropositivity rate was 78.5% and was significantly lower in patients under immunosuppressive therapy (75.7 vs 93.2%, P = 0.009). No difference regarding the vaccination type was observed. Glucocorticoids, mycophenolate-mofetil, TNF inhibitors, tocilizumab, abatacept and rituximab were all associated with non-response after proper vaccination. The risk was highest under RTX therapy (OR 0.004, 95% CI 0.001, 0.023, P &lt; 0.0001). A strong negative correlation was observed between time since vaccination with an mRNA vaccine and anti-S antibody levels (r=–0.6149, P &lt; 0.0001). In patients without humoral response, a T-cell response was found in 50%.</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>COVID-19 vaccination in patients with AIIRD is effective using any approved vaccine. Humoral response might be impaired depending on the individual immunosuppressive medication. The risk of non-response is highest under rituximab therapy. Anti-S IgG antibody levels wane over time after mRNA vaccination. Importantly, 50% of humoral non-responders showed a T-cellular response, suggesting T-cell-mediated protection to a certain extent.</jats:p> </jats:sec>