Original article
COVID-19 and the Risk of Relapse in Multiple Sclerosis Patients: A Fight with No Bystander Effect?

https://doi.org/10.1016/j.msard.2021.102915Get rights and content

Highlights

  • COVID-19 contraction did not increase the risk of relapse in MS patients six months post-infection.

  • MS relapses incidence rate was lower in patients who contracted COVID-19 than in patients who did not.

  • The risk of relapse was not affected by the severity of COVID-19 and hospitalization.

Abstract

Background

COVID-19 is speculated to increase the likelihood of relapsing-remitting multiple sclerosis (RRMS) exacerbation.

Objective

To investigate the association between contraction of COVID-19 and incidence of acute MS attacks in RRMS patients six months post-infection.

Methods

This retrospective cohort study compares the risk of relapse in RRMS patients with (n=56) and without COVID-19 (n=69). Incidence of relapse was recorded for six-month following contraction of COVID-19. Incidence of RRMS exacerbation in patients with COVID-19 was compared to patients without COVID-19 (the independent control group) and the same patients six months prior to the COVID-19 pandemic.

Results

A lower incidence rate of RRMS exacerbation was observed in patients that contracted COVID-19 than in patients who did not contract COVID-19 (incidence rate ratio: 0.275; p=0.026). Self-controlled analysis showed no significant difference in relapse rates before the COVID-19 pandemic and after contracting COVID-19 (p=0.222). The relapse risk was not different between patients who had been hospitalized due to COVID-19 severity and those who had not (p=0.710).

Conclusion

COVID-19 contraction may not increase the risk of acute MS attacks shortly following contraction. We hypothesize that COVID-19-associated lymphopenia may partly preclude the autoreactive memory cells from expansion and initiating relapses through a so-called bystander effect of COVID-19 infection.

Keywords

Multiple Sclerosis
Relapsing-Remitting Multiple Sclerosis
COVID-19
SARS-CoV-2

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