Risk of MS relapse and deterioration after COVID-19: A systematic review and meta-analysis

Background: Upper respiratory viral infections have long been considered triggers for multiple sclerosis (MS) relapse and exacerbation. The possible effects of SARS-CoV-2 infection on MS relapse and deterioration remain controversial. Methods: We systematically searched PubMed, Scopus, Embase, Cochrane, and Web of Science databases to find relevant studies assessing changes in relapse rates or Expanded Disability Status Scale (EDSS) following COVID-19 in people with MS. Meta-analyses were performed, and to investigate sources of heterogeneity, subgroup analysis, meta-regression, and sensitivity analysis were conducted. Results: We included 14 studies in our systematic review and meta-analysis. The meta-analysis demonstrated that COVID-19 was not associated with a rise in relapse rate (risk ratio (RR): 0.97, 95 % confidence interval (CI): 0.67, 1.41, p-value: 0.87) or a rise in EDSS (standardized mean difference (SMD): −0.09, 95 % CI: −0.22, 0.03, p-value: 0.13). The analysis of EDSS changes indicated a significant heterogeneity (I²: 55 %, p-value: 0.01). Other analyses were not statistically significant. Conclusions: COVID-19 infection was not associated with an increased risk of relapse and clinical deterioration in people with MS.