The relationship between COVID-19 infection, COVID-19 vaccination, and the risk of relapse in people with Multiple Sclerosis (MS) is a topic of significant interest and concern. MS is a chronic neurological condition characterized by episodes of new or worsening symptoms called relapses, which reflect inflammatory activity in the central nervous system. Understanding whether COVID-19 infection or vaccination influences relapse risk is crucial for managing MS safely during the pandemic and beyond.
COVID-19 infection can trigger a strong immune response, sometimes leading to an excessive release of inflammatory molecules called cytokines. This “cytokine storm” can disrupt the blood-brain barrier and potentially worsen neuroinflammation. Since MS involves immune-mediated damage to nerve cells and their protective coverings, there is a theoretical concern that COVID-19 infection might provoke or worsen MS relapses. Indeed, the virus has neuroinvasive potential, and some patients with neuroimmunological diseases have experienced neurological symptoms during or after COVID-19 infection. However, the evidence so far suggests that while COVID-19 can cause neurological symptoms, it does not consistently increase the risk of MS relapses. The immune dysregulation caused by COVID-19 may persist for some time, but it is not yet clear if this leads to sustained worsening of MS disease activity. Importantly, many people with MS are on immunosuppressive or immunomodulatory therapies, which can alter their immune response to infection and complicate the picture.
On the other hand, COVID-19 vaccination has been extensively studied in people with MS. Vaccines, especially mRNA vaccines like Pfizer-BioNTech and Moderna, have been shown to be safe and do not increase the risk of MS relapses. This is reassuring because vaccines stimulate the immune system to recognize the virus without causing the disease itself. The immune activation from vaccination is controlled and transient, unlike the uncontrolled inflammation that can occur during actual infection. People with MS are encouraged to receive COVID-19 vaccines and booster doses to reduce their risk of severe COVID-19 illness, which could potentially trigger relapses or other complications. Vaccination is particularly important for those on immunosuppressive medications, as they are at higher risk of severe COVID-19.
It is generally recommended that people with MS avoid vaccination during an active relapse or while relapse symptoms are worsening. Waiting until symptoms stabilize helps ensure that any new symptoms after vaccination are not confused with relapse activity. For those on disease-modifying therapies (DMTs), timing of vaccination may be coordinated with treatment schedules to optimize vaccine effectiveness without increasing relapse risk.
In summary, while COVID-19 infection can cause immune changes that might theoretically influence MS activity, current data do not show a clear increase in relapse risk directly attributable to the infection. Conversely, COVID-19 vaccines are considered safe for people with MS and do not increase relapse rates. Vaccination remains a key protective measure to prevent severe COVID-19, which itself could pose a greater risk to MS stability. People with MS should discuss their individual situation with their healthcare providers to tailor vaccination timing and MS treatment plans appropriately.
