LAUSR

OBJECTIVES Juvenile onset systemic lupus erythematosus (jSLE) has a severe presentation and a remitting course. Patients with jSLE carry an increased vulnerability to infections, which also act as triggers of disease flare. Thus, vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important tool in jSLE. The objective of this study is to evaluate the tolerability and the safety of anti-SARS-COV-2 vaccination, including the booster, in a monocentric cohort of jSLE patients. METHODS Clinical records of jSLE patients who received at least one dose of any anti-SARS-CoV-2 vaccine were retrospectively reviewed. Data about disease activity, treatment, anti-SARS-CoV-2 vaccination and COVID-19 infection were collected. RESULTS 65 jSLE patients received at least one dose of anti-SARS-CoV-2 vaccination, while 46 patients completed the schedule with the booster. The rate of mild-moderate adverse events was 66%, mainly comprising fever, fatigue, arthromyalgias and pain at injection site. The rate of adverse events after the booster was similar to that registered after the first two doses. No significant changes after SARS-CoV-2 vaccination in BILAG and SLEDAI were observed. Disease flare rate (mainly lupus nephritis) after immunization was 10.8%. Flares occurred predominantly in patients with moderate disease activity before immunization; accordingly, SLEDAI≥4 identified patients at risk of flare while LLDAS plays a protective role against post-vaccination flare. CONCLUSIONS This study confirms that anti-SARS-CoV-2 vaccination in jSLE is well-tolerated; a strict clinical monitoring and a thoughtful choice of vaccination timing should be devoted to patients not in LLDAS due to the risk of post-vaccine flare.