COVID-19 in multiple sclerosis patients: susceptibility, severity risk factors and serological response.

Background and purpose Information regarding multiple sclerosis (MS) patients with the 2019 novel coronavirus disease (COVID-19) is scarce. The study objective was to describe the incidence and characteristics of MS patients with COVID-19, to identify susceptibility and severity risk factors and to assess the proportion of positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serologies according to disease-modifying treatments. Methods This was a retrospective study of an MS cohort analysing data collected between February and May 2020. Cases were identified through an email survey and clinical visits. The relationship of demographic and MS characteristics with COVID-19 and of the disease-modifying treatments with SARS-CoV-2 serostatus were examined. Results Data from 48 suspected cases out of 758 valid respondents and from 45 COVID-19 cases identified through clinical visits were collected. Incidence was 6.3%. Nineteen (20.3%) patients were hospitalized and two (2.2%) died. Multivariable models determined that age (odds ratio [OR] per 10 years 0.53, 95% confidence interval [CI] 0.34-0.85), contact with a confirmed case (OR 197.02, 95% CI 56.36-688.79), residence in Barcelona (OR 2.23, 95% CI 1.03-4.80), MS duration (OR per 5 years 1.41, 95% CI 1.09-1.83) and time on anti-CD20 treatment (OR per 2 years 3.48, 95% CI 1.44-8.45) were independent factors for presenting COVID-19 and age (OR per 10 years 2.71, 95% CI 1.13-6.53) for a severe COVID-19. Out of the 79 (84.9%) with serological test, 45.6% generated antibodies, but only 17.6% of those on anti-CD20 therapies. Lymphopaenia or immunoglobulin levels did not relate to COVID-19. Conclusions Multiple sclerosis patients present similar incidence, risk factors and outcomes for COVID-19 as the general population. Patients treated with an anti-CD20 therapy for a longer period of time might be at a higher risk of COVID-19 and less than 20% generate an antibody response. Only age was related to severity.