Q: Does COVID-19 cause MS to relapse?
Does COVID-19 cause MS to relapse?
You may be aware, or not, that about a third of relapses are preceded by an infection, which are typically viral infections. The observation that infections trigger relapses was made in the pre-DMT (disease-modifying treatment) era and possibly doesn't hold for pwMS who are on a DMT. Therefore if you have MS and are not on a DMT I would think coronavirus infections, like other viral infections, could trigger relapses. However, I suspect if you are on a DMT, in particular a high-efficacy DMT, then COVID-19 won't trigger a relapse.
Does COVID-19 cause PSEUDO-relapses?
So called pseudo-relapses occur when you get a recurrence of old symptoms that result in transient worsening in neurological function. These transient symptoms alway involve a previously affected pathway unless you have primary progressive MS when the pseudorelapse can unmask new symptoms. What causes pseudorelapses is usually temperature-related conduction block in a demyelinated or vulnerable neuronal pathway. This is why when many pwMS get a fever they get transient symptoms.
I don't like the term pseudorelapses because many people with quite advanced MS who have an infection and get worsening during the infection often don't recover to back to their baseline. These episodes can't be called a relapse because by defintion a relapse has to occur in the absence of infection and/or a fever. I personally think we should call this phenomenon infection-related worsening and manage it as a form of MS disease-activity. This is one of the motivations for trying to prevent recurrent infections in pwMS as a strategy to slow down worsening disability.
Please note that NSAIDs or non-steroidal anti-inflammatory drugs are not being recommended for controlling temperature during the COVID-19 pandemic. The French health authorities have noted an increased incidence of severe COVID-19 in young patients on NSAIDs. The recommendation is to rather use paracetamol or acetaminophen as antipyretic.
Date & Disclaimer: 18-March-2020; please note this information will be time limited and will change as new data emerges.