Safety Profile of SARS-CoV-2 Vaccination in Patients with Lupus Nephritis: A Retrospective Study

<b>Objectives:</b> Vaccination against SARS-CoV-2 has been vital in alleviating the spread of the recent pandemic. We aimed to estimate the frequency and type of adverse events related to SARS-CoV-2 vaccine in patients with lupus nephritis (LN), and assess its impact, if any, on the risk of subsequent reactivation of nephritis. <b>Methods:</b> This was a retrospective, multicenter study which included patients with biopsy-proven LN, who had received at least one vaccine dose. Patients who ended up with end-stage kidney disease (ESKD) prior to vaccination or were diagnosed with LN after vaccination were excluded. Adverse events, systemic or local, COVID-19 outcomes (full recovery, death, or long COVID-19), outcome of LN (remission, refractory disease, relapse, ESKD or death), demographics, laboratory measurements, and immunosuppressive regimens were recorded. <b>Results:</b> Sixty-seven patients were included. The median age was 33 (20-46) years. Induction therapy for LN was administered to 92.5% of patients and 74.6% received maintenance therapy. Of these, 94.02% were in remission at vaccination. The BNT162b2 mRNA vaccine was administered in 97.01% of cases, with mild systemic adverse symptoms in 28.35% (myalgias 17.91%, headache 13.43%, arthralgias 13.43%, and fever 10.44%) and local adverse effects in 35.82% (pain 25.37%, swelling 13.43%). Overall, among patients in remission upon vaccination, two (3.17%) experienced a LN relapse within 5.75 (±0.25) months, while 75% of those with active disease at vaccination achieved remission within 21 (±2) months. <b>Conclusions:</b> SARS-CoV-2 vaccination appears safe for LN patients without serious adverse events occurring, and there is no significant impact in the clinical course of the disease.