Humoral Response of Different Types of SARS-CoV-2 Vaccines in Patients with Autoimmune Rheumatic Diseases: Experiences from a Serbian Cohort.
Data are scarce on the immunogenicity of coronavirus disease 2019 vaccines in patients with autoimmune rheumatic diseases (ARD). To measure the immunoglobulin G (IgG) response after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization and to evaluate clinical characteristics associated with seropositivity. Samples were collected after the second and third doses of the three different types of vaccines in ARD patients. Seroconversion rates and IgG antibody S1/S2 titers were measured. The type of ARD diagnosis and previous treatment had no significant impact on the serum IgG antibody levels measured after the second (P = 0.489 and P = 0.330, respectively) and boost dose (P = 0.441 and P = 0.446, respectively). What made a significant difference regarding serum IgG antibody levels after the second dose was the type of SARS-CoV-2 vaccine. The difference was highly statistically significant for all vaccine types (P = 0.001 with the highest odds ratio for the mRNA vaccine). After the boost with the mRNA vaccine, all patients achieved a high level of serum IgG antibody levels (t = 10.31, P = 0.001). No ARD patients experienced serious post-vaccinal reactions. Eight patients developed COVID-19 before the boost dose. In ARDs patients, the highest level of serum IgG antibody against S1/S2 proteins was achieved with the mRNA vaccine, irrespective of the therapy applied or the type of the disease. We recommend a booster dose with mRNA vaccine in all ARDs for the highest SARS-CoV-2 protection without serious post-vaccinal reactions observed.