ABSTRACT
OBJECTIVES: Scanty data on the anti- SARS-CoV-2 IgG level decay after two-dose BNT162b2 vaccination have been published in patients with psoriatic arthritis (PsA) on TNF inhibitors (TNFi). Similarly, no reports on the immunogenicity of a booster dose in such patients have been provided yet.We aimed to investigate the IgG level decay after two-dose BNT162b2 vaccination and the immunogenicity and safety of the booster dose in PsA patients on TNFi. METHODS: Forty patients with classified PsA on TNFi undergoing booster dose with the BNT162b2 mRNA SARS- CoV-2 vaccine (BioNTech/Pfizer) were enrolled. Fifteen days after the third shot, serum IgG levels against SARS-CoV-2 (Abbott®ARCHITECT i2000SR, positivity cut-off 50 AU/mL) were assayed in all patients. Clinimetrics and treatment data were gathered. TNFi treatment was not discontinued. Sera from healthcare professionals were considered as healthy controls for 1:1 propensity score-matching. Student's t-test and logistic regression were used for investigating differences in immunogenicity between groups and predictors of antibody response. RESULTS: Even though the decay of IgG levels showed similar magnitude between groups, PsA patients had a lower IgG level than matched controls at 4 months after two-dose vaccination (2009.22±4050.22 vs. 6206.59±4968.33 AU/mL, respectively p=0.0006). Booster dose restored IgG levels to a similar extent in both groups (15846.47±12876.48 vs. 20374.46±12797.08 AU/ml p=0.20, respectively). Clinical Disease Activity Index (CDAI) did not change before and after vaccination (6.68±4.38 vs. 4.95±4.20, p=0.19). CONCLUSIONS: A BNT162b2 booster dose should be recommended in PsA patients on TNFi as its administration restores anti-SARS-CoV-2 IgG levels similar to healthy individuals.