Researchers reported on the levels of antibodies from the second to third severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccination in multiple sclerosis (MS) patients treated with anti-CD20 therapy. Their findings were published in Multiple Sclerosis and Related Disorders.

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Anti-CD20 therapy is widely used to treat MS because it targets B-lymphocytes and causes cell lysis, which reduces disease activity in both progressive and relapsing MS. The medical community has been particularly worried about the negative effects of the COVID-19 pandemic on vulnerable patients, such as those on B-cell depleting therapy. 

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The authors of the study wrote, “Several studies confirm that vaccination, in general, generates a decreased humoral response in anti-CD20 treated patients.” Studies also suggest that extending the interval between anti-CD20 treatments and having higher levels of B-cells at the time of vaccination improve patients’ response to vaccination. 

Bajwa and colleagues wanted to determine whether additional mRNA SARS-CoV-2 vaccination could increase levels of antibodies generated in MS patients who were on anti-CD20 therapy (ocrelizumab). They also set out to investigate whether a third dose of vaccine could increase T-cell responses, as well as the percentage of seropositive individuals among participants. Results regarding the effects of the first and second vaccine dose on this group of patients had already been published in another paper.

This study involved patients with MS who were taking ocrelizumab and had received 2 doses of the mRNA-SARS-CoV-2 vaccination, but not a third vaccine dose yet. Blood samples were collected 0 to 7 days before the participants received their third vaccine dose and 2 to 4 weeks after they received the vaccine. Various biological tests were then carried out. 

The authors of the study highlighted the following results: 

  • The antibody levels of participants were sustained after receiving the third vaccine dose. 
  • No significant difference in T-cell reactivity was found from the second to third vaccine dose. 
  • There was no association between antibody levels and the time from the second to third vaccine dose. 
  • There was no association between antibody levels and the time from the last anti-CD20 infusion to the third vaccine dose. 

The research team wrote, “In summary, in contrast to prior studies, in this longitudinal cohort we found no significant increased protective benefit from a humoral or cellular perspective with administration of a third SARS-CoV-2 mRNA vaccination.”


Bajwa HM, Novak F, Nilsson AC, et al. Persistently reduced humoral and sustained cellular immune response from first to third SARS-CoV-2 mRNA vaccination in anti-CD20-treated multiple sclerosis patients. Mult Scler Relat Disord. Published online March 6, 2022. doi:10.1016/j.msard.2022.103729