COVID-19 has no impact on disease activity, progression and cognitive performance in people with multiple sclerosis: a 2-year study.

Background: Sequelae of COVID-19 in people with multiple sclerosis (PwMS) have not been characterised. We explored whether COVID-19 is associated with an increased risk of disease activity, disability worsening, neuropsychological distress and cognitive dysfunction during the 18-24 months following SARS-COV-2 infection.

Methods: We enrolled 174 PwMS with history of COVID-19 (MS-COVID) between March 2020 and March 2021 and compared them to an age, sex, disease duration, Expanded Disability Status Scale (EDSS), and a line of treatment-matched group of 348 PwMS with no history of COVID-19 in the same period (MS-NCOVID). We collected clinical, MRI data and SARS-CoV2 immune response in the 18-24 months following COVID-19 or baseline evaluation. At follow-up, PwMS also underwent a complete neuropsychological assessment with brief repeatable battery of neuropsychological tests and optimised scales for fatigue, anxiety, depression and post-traumatic stress symptoms.

Results: 136 MS-COVID and 186 MS-NCOVID accepted the complete longitudinal evaluation. The two groups had similar rate of EDSS worsening (15% vs 11%, p=1.00), number of relapses (6% vs 5%, p=1.00), disease-modifying therapy change (7% vs 4%, p=0.81), patients with new T2-lesions (9% vs 11%, p=1.00) and gadolinium-enhancing lesions (7% vs 4%, p=1.00) on brain MRI. 22% of MS-COVID and 23% MS-NCOVID were cognitively impaired at 18-24 months evaluation, with similar prevalence of cognitive impairment (p=1.00). The z-scores of global and domain-specific cognitive functions and the prevalence of neuropsychiatric manifestations were also similar. No difference was detected in terms of SARS-CoV2 cellular immune response.

Conclusions: In PwMS, COVID-19 has no impact on disease activity, course and cognitive performance 18-24 months after infection.