Effect of COVID-19 pandemic on disease activity in multiple sclerosis patients treated with hematopoietic stem cell transplantation.

Abstract

It is still debated whether COVID-19 pandemic affected disease activity in people with (pw) autoimmune diseases, including multiple sclerosis (MS), therefore its impact was explored in pwMS not receiving continuative disease-modifying therapy (DMTs) after previous treatment with autologous haematopoietic stem cell transplantation (AHSCT). PwMS treated with AHSCT who were in disease remission without receiving DMTs during the pandemic, and who performed a follow-up at our centre in the study period were included. Data on SARS-CoV-2 infection and vaccination were recorded, with details on adverse events and clinical-radiological disease activity. 36 pwMS (31 females; 86%) were included: 23 (64%) relapsing-remitting (RR-) and 13 secondary-progressive (SP-)MS. Thirty-three pwMS (92%) were vaccinated with anti-SARS-CoV-2 mRNA vaccines. Thirteen (36%) patients developed mild to moderate COVID-19 a median of 58 (4 - 224) months after AHSCT; 7 (54%) of these cases were not vaccinated yet. Transient neurological symptoms after vaccination or infection were reported in 9% and 36% of the cases, respectively. The rate of new inflammatory events (relapses or asymptomatic MRI activity) after AHSCT increased from 0.006 (1 asymptomatic new lesion/159 patient-years) before the pandemic to 0.083 (5 relapses plus 2 asymptomatic MRI activities/84 patient-years) since pandemic start (p=0.004). PwMS with a history of highly active disease and who are untreated, or who are receiving moderate efficacy DMTs, might be more vulnerable to disease reactivation possibly elicited by exogenous triggers. Careful monitoring and further investigation are warranted to ascertain whether special precautions are needed in these cases.