Abstract
Vaccination is the most effective preventive measure to control the spread of COVID-19 and reduce associated complications. This study aims to evaluate the efficacy and safety of mRNA COVID-19 vaccines in patients with systemic lupus erythematosus (SLE). A total of 41 adult SLE patients receiving two doses of the SARS-CoV-2 mRNA Comirnaty-BioNTech/Pfizer vaccine were enrolled. The quantitative determination of anti-trimeric spike protein-specific IgG antibodies to SARS-CoV-2 was assessed before (T0), 21 days after the administration of the first dose of the vaccine (T1), and between 21 and 28 days after the second dose (T2). They were compared with the same determinations from a cohort of 29 patients with C1-esterase inhibitor deficiency hereditary angioedema (C1-INH-HAE) as controls. All the SLE patients and controls demonstrated a positive serological response after a single dose of the vaccine (T1), which significantly increased after the second dose (T2). No significant difference was found between SLE patients and controls at T1 [t(52.81) = -0.68; p = 0.49] and at T2 [t(67.74) = -0.22; p = 0.825]. Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) analysis showed that the vaccine did not influence SLE activity or caused disease flare in our cohort. In conclusion, COVID-19 vaccines produced a satisfactory response in SLE patients without variation in the disease activity.