Impact of Distinct Therapies on Antibody Response to<scp>SARS‐CoV</scp>‐2 Vaccine in Systemic Lupus Erythematosus

To date, the only study that has assessed the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 mRNA) vaccine in systemic lupus erythematosus (SLE) observed a moderate response, but the sample size precluded an accurate analysis of the effect of individual drugs. Therefore, we evaluated the immunogenicity of an inactivated SARS-CoV-2 vaccine (Sinovac-CoronaVac) and the influence of different medications in SLE. Safety was also assessed.We conducted a prospective controlled study of 232 SARS-CoV-2-naive SLE patients and 58 SARS-CoV-2-naive controls who were vaccinated with 2 doses of Sinovac-CoronaVac with a 28-day interval (day 0/day 28 [D0/D28]). Immunogenicity analysis at D0/D28 and D69 included anti-SARS-CoV-2 S1/S2 IgG seroconversion (SC) and neutralizing antibodies (NAb) positivity. The influence of individual drugs on immune response and safety was assessed.Patients and controls were well balanced for age (P = 0.771). At D69, SLE patients showed a moderate SC (70.2% versus 98.1%; P 0.001) and moderate frequency of NAb positivity (61.5% versus 84.6%; P = 0.002), although both frequencies were lower than in controls. Factors associated with lower SC in univariate analysis at D69 were prednisone use (odds ratio [OR] 0.215 [95% confidence interval (95% CI) 0.108-0.427], P 0.001) and mycophenolate mofetil (MMF) use (OR 0.201 [95% CI 0.107-0.378], P 0.001), whereas hydroxychloroquine (HCQ) use led to a 2.5 increase in SC (P = 0.011). SLE patients who were receiving HCQ monotherapy had similar SC to controls at D69 (100% versus 98.1%; P = 1.000). In multivariate analysis, prednisone and MMF use were independently associated with lower SC (P 0.001) and NAb positivity (P 0.001). Safety analysis revealed no moderate/severe adverse events.Sinovac-CoronaVac has a moderate immunogenicity in SARS-CoV-2-naive SLE patients with an excellent safety profile. We further demonstrate that HCQ may improve SC, whereas prednisone and MMF had a major deleterious effect in vaccine response, reinforcing the need to investigate the role of temporary MMF withdrawal or a vaccine-booster dose (ClinicalTrials.gov identifier: NCT04754698).