LAUSR

mRNA vaccine (Pfizer/BioNTech or Moderna). There were no nonresponders (antibody titres below the cut-off); however, the patient group had significantly lower levels of IgG against SARS-CoV-2 (mean SD 2053 1218 BAU/mL, range 98.2–3840 BAU/mL) compared with the control group (1102 2685 BAU/ mL; 793–3840 BAU/mL). Our data showed no difference in the rate of seroconversion, but significantly lower titres were observed in patients with psoriasis treated with biologic monotherapy, and there were no significant differences between the four treatment groups. These lower titres suggest the need for the recommended booster shot; however, the exact scheduling for patients with psoriasis on biologics has to be determined. The limitations of our study include small number of participants, not testing cell-mediated immunity, and not matching patients and controls for age. Further controlled studies including large number of participants, with longitudinal design, and assessing immunological and clinical efficacy simultaneously are needed.