Immunogenicity and safety of BNT162b2 vaccination in adolescents with systemic lupus erythematosus

Objectives: We evaluated the immunogenicity and safety of BNT162b2 vaccination in adolescents with systemic lupus erythematosus (adoSLE) receiving either high- or low-dose immunosuppressant (High-IS and Low-IS). Methods: Patients aged 12–18 years diagnosed with SLE were enrolled. High-IS was defined as >7.5 mg/day prednisolone or with other immunosuppressant, while Low-IS was defined as only ≤7.5 mg/day of prednisolone and no immunosuppressant. Two doses of BNT162b2 vaccination were given 4 weeks apart, followed by a booster (third) dose at 4–6 months later. Anti-spike receptor binding domain (anti-RBD) IgG against Wuhan, neutralising antibody (NT) against Wuhan and Omicron variants, and cellular immune response by IFN-γ-ELISpot assay were evaluated following vaccination. Adverse events (AEs) and SLE flare were monitored. Results: A total of 73 participants were enrolled, 40 and 33 in the High-IS and Low-IS group, respectively. At 4 weeks following the 2nd dose, overall anti-RBD IgG seropositivity was 97.3%, with no difference between the groups (p =.498). AdoSLE on High-IS had lower anti-RBD IgG (p <.001), Wuhan NT (p <.001), and IFN-γ-ELISpot (p =.022) than those on Low-IS. A 3rd dose induced significantly higher antibody responses than after the 2nd dose (p <.001) in both groups and established seroconversion against Omicron variants, with persistent lower antibody levels in High-IS group. SELENA-SLEDAI scores within 12 weeks after 2-dose vaccination was higher than before vaccination (3.1 vs 2.5; p <.036); however, the occurrence of disease flare by SELENA-SLEDAI flare index was not different after vaccination compared to before vaccination, consistent across groups. Non-severe AEs occurred similarly in both groups. Conclusion: AdoSLE on High-IS induced lower SARS-CoV-2 vaccine immune responses than Low-IS. Vaccination can increase disease activity and requires close monitoring for disease flare.