Safety of disease-modifying treatments in SARS-CoV-2 antibody-positive multiple sclerosis patients

BACKGROUND: Coronavirus disease 2019 (COVID-19) raises particular concerns for people with multiple sclerosis (PwMS) on disease-modifying treatments (DMTs), and for physicians caring for them. The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on PwMS receiving DMTs that inhibit immune cell trafficking, such as natalizumab (NTZ) and fingolimod (FTY), remains to be determined, as do the possible effects of these drugs on both the infection and the related disease. AIMS: To describe self-reported COVID-19 symptoms and disease severity in PwMS on NTZ or FTY who received serology confirmation of SARS-CoV-2 infection. METHODS: From 27th April to 3rd May 2020, telephone interviews were conducted with 140 PwMS under treatment with NTZ or FTY in order to collect structured data on multiple sclerosis (MS) and COVID-19. The patients, all followed at our center, were classified as symptomatic, paucisymptomatic or asymptomatic on the basis of their self-reported clinical characteristics. COVID-19 severity was rated on a 7-point ordinal scale. In addition, in the period 4th May to 3rd June 2020 SARS-CoV-2 serology testing, using the Roche SARS-CoV-2 IgG assay (Elecsys(Ⓡ)), was performed in 104/140 (74.2%) of the interviewed PwMS (50 treated with NTZ and 54 with FTY). RESULTS: 14/104 (13.4%) PwMS on NTZ or FTY had anti-SARS-CoV-2 antibodies: 8 met the criteria for asymptomatic, 3 for paucisymptomatic and 3 for symptomatic COVID-19 (COVID-19 severity score lower than 3). None of them required hospitalization or showed severe COVID-19 complications. CONCLUSIONS: Despite the relatively high SARS CoV-2 seroprevalence found in this sample of PwMS, all the positive cases showed either no or only mild COVID-19 symptoms. These reassuring findings indicate a lack of COVID-19 complications in PwMS on DMTs and support the hypothesis that it is safe to maintain ongoing treatment with these drugs in the current setting.