ABSTRACT
Background: The effects of MS disease modifying therapies (DMTs) on COVID-19 morbidity and mortality have been studied in clinician-reported registries, but the true prevalence of SARSCoV-2 infection and its outcomes in the MS population receiving DMTs are unknown. Objectives: To assess the prevalence of SARS-CoV-2 infection and its outcomes, and their association with individual DMTs among all MS patients receiving DMTs in England. Aims: To understand the magnitude of COVID-19's impact on a population of MS patients receiving DMTs. Methods: We analysed merged national databases to ascertain the rate of SARS-CoV-2 positive tests and COVID-19 in-hospital mortality among all MS patients receiving DMTs in England from 1/02/2020 to 27/03/2021. The National Health Service (NHS) England and NHS Improvement collect prescribing and dispensing data on all MS DMTs. Public Health England collects data on all SARS-CoV-2 tests and COVID-19 in-hospital deaths. Further clinical data collection on a random sample of patients who tested positive (cases) or were not tested (controls) for SARS-CoV-2 is ongoing in multiple centres to establish risk factors of adverse COVID-19 outcomes without selection bias. Results: A total of 35556 MS patients had received a DMT. Their mean (standard deviation) age was 44 (12) years. A total of 16,108 patients (45.3%) were tested for SARS-CoV-2, and 2000 (5.6%) tested positive with a mean age of 42 (12) years. Twentysix patients with a positive test (1.3%) died in hospital. Their mean age was 54 (16) years. The age-standardised mortality ratio (95% confidence interval) of the MS versus the general population was 1.2 (0.7-1.7). There was no clear difference between individual DMTs in their rates of positive tests or inhospital mortality. Detailed data on 79 randomly selected patients with a positive test has been collected at two centres so far. Their mean age is 44 (11) years and 55 (69.6%) are women. Five were hospitalised due to COVID-19 out of whom one was admitted to an intensive therapy unit and died. Data will be updated and reanalysed prior to ECTRIMS 2021. Conclusions: So far, COVID-19 does not appear to significantly increase the risk of mortality in MS patients on DMTs compared to the general population, in this large population study.