This evidence synthesis has been compiled by members of the CITF Secretariat and does not necessarily represent the views of all CITF members.

By Mariana Bego 

Multiple sclerosis (MS) is an autoimmune disorder that is often treated with drugs that deplete B cells and therefore interfere in the process of antibody production. Indeed, MS patients being treated with certain medications have no detectable antibody response after two doses of the COVID-19 vaccine. While these vaccines have been proven safe for these patients, a study in Therapeutic Advances in Neurological Disorders suggests the overall protection they confer requires further evaluation. It is important to keep these patients in the current vaccination priority group, but with a more rigorous follow up.

Patients under certain treatments for Multiple Sclerosis are unable to develop a humoral IgG response after two doses of the COVID-19 vaccine.

  • Only 22.7% of patients treated with Ocrelizumab and 3% of patients treated with Fingolimod developed a SARS-COV-2-specific IgG response a month after the second vaccine dose (independent of their B cell counts).
  • What is unclear is whether these patients developed a cellular immune response to the vaccine and the level of protection that the vaccination conferred them. 

Multiple sclerosis (MS) is an autoimmune disorder of the brain and spinal cord. Immunomodulatory drugs have been used for over two decades to treat relapsing MS.

Drugs that deplete B cells in particular have shown efficacy for treating primary progressive MS but decreasing B-cell number or function may interfere in the process of antibody production. Overall, the specificity of the B-cell subset they target differs considerably. Fingolimod and Cladribine can act on both B and T cells, and Ocrelizumab depletes mature B cells.

Researchers from Israel recently assessed antibody production after vaccination in a cohort of Multiple Sclerosis patients. They reported an excellent level of protective humoral immunity within 29.5–55 days after two doses of COVID-19 vaccine in healthy subjects (46 of the 47 individuals in this group had antibodies), untreated MS patients (all 32 individuals had antibodies), and MS patients treated with Cladribine (all 23 individuals had antibodies). However, merely 22.7% of patients treated with Ocrelizumab developed a humoral immune response irrespective of normal white blood count. Even more strikingly, only 3% of the Fingolimod-treated MS patients had detectable levels of SARS-COV-2 antibodies. Furthermore, these patients also had very low counts of T and B cells.

Based on these results, the authors recommended postponing Ocrelizumab treatment in MS patients willing to be vaccinated and did not recommend vaccinating MS patients treated with Fingolimod.

It remains unclear, however, whether MS patients develop a cellular immune response to the vaccine and the overall levels of protection that vaccination confers them. That said, many expert organizations, including the National Multiple Sclerosis Society, recommend that all patients with MS should get vaccinated against COVID-19. COVID-19 vaccines have been shown to be safe for these patients. There have not been publicized reports suggesting a higher prevalence of side effects, worsening MS symptoms, or an immediate increase in the rate of acute relapses. Ultimately, the risks posed by COVID-19 infection in MS patients far outweigh potential risks from the vaccine, and even a little protection is better than none. In addition, as seen in our second blog post for this week, members of the same household and close contacts should also be vaccinated against COVID-19, when able to do so, to decrease the impact of the virus in susceptible populations that may not get a strong protection from the vaccines.

Achiron A, Mandel M, Dreyer-Alster S, Harari G, Magalashvili D, Sonis P, Dolev M, Menascu S, Fletcher S, Falb R, Gurevich M. Humoral immune response to COVID-19 mRNA vaccine in patients with multiple sclerosis treated with high-efficacy disease-modifying therapies. Ther Adv Neurol Disord. 2021 Apr 22. doi: 10.1177/17562864211012835