Does COVID-19 Lead to Greater Relapse Risk, Deterioration in Multiple Sclerosis?

COVID-19 infection does not increase relapse risk or worsen Expanded Disability Status Scale (EDSS) scores in patients with multiple sclerosis (MS), according to study results published in Multiple Sclerosis and Related Disorders.

Previous studies have suggested a link between upper respiratory viral infection and MS relapse and disease exacerbation; however, data regarding the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on MS is unclear.

Researchers conducted a systematic review and meta-analysis to determine differences in relapse rates and EDSS scores in patients with MS with and without COVID-19 infection. Subgroup, meta-regression, and sensitivity analyses were also conducted to explore sources of heterogeneity.

PubMed, Scopus, Embase, Cochrane, and Web of Science were used to identify case-controlled, cross-sectional, or cohort studies that evaluated relapse rates or changes in EDSS scores after patients with MS contracted COVID-19. Studies had to be conducted prior to November 2023 and needed to have assessed patients with MS before and after contracting COVID-19 or compare patients with MS who did and did not contract COVID-19. Studies that did not provide an exact follow-up duration or provide any comparison were excluded from the study.  

After identifying 8459 potentially eligible studies, 14 were selected for systematic review. Across the 14 articles, 3453 patients were studied, the majority of which were women (n=2484; 71.9%).

Based on MS type:

• 2932 patients had relapsing-remitting MS,
• 131 patients had primary progressive MS,
• 315 had secondary progressive MS,
• 31 patients had clinically isolated syndrome,
• 14 had radiologically isolated syndrome, and
• 30 cases had an unreported MS type.

Ten studies comprised 2783 patients with MS evaluated changes in relapse rates before and after contracting COVID-19, compared the relapse rates of those who did and did not contract COVID-19, or considered both.

Meta-analysis revealed that changes in relapse rates in patients following COVID-19 infection were not significant (risk ratio [RR], 0.97; 95% CI, 0.67-1.41; P =.87).

Subgroup analysis revealed that changes in relapse rates in patients before and after contracting COVID-19, as well as changes in relapse rates in 2 populations (infected vs not infected), were also insignificant (P =.64). The included studies did not indicate significant heterogeneity for overall results (I², 30%; P =.16).

Ten studies comprised 2712 patients with MS assessed changes in EDSS scores following COVID-19 infection. The studies compared 2 populations (infected vs not infected), assessed the infection effects on 1 population, or considered both. Meta-analysis did not suggest COVID-19 significantly impacted EDSS scores (standardized mean difference, -0.09; 95% CI, -0.22 to 0.03; P =.13). The included studies also indicated significant heterogeneity for overall results (I², 55%; P =.01). 

Study limitations included the small number of studies and small sample sizes of each study. Additionally, all of the studies were conducted in West Asia or Europe, which limits the generalizability of study results to participants of diverse racial and ethnic backgrounds. The researchers also did not report exact pathological COVID-19 variants, which impacts the ability to compare the effects of different variants on the risk of relapse and EDSS score in patients with MS.

“More studies from different countries and regions with larger sample sizes, controlling for MS therapy adherence, vaccination, and demographic factors are needed to provide definite information about the potential effect of COVID-19 on MS progression,” the researchers concluded.