Researchers from Brazil reported cases of relapse of multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD) after vaccination with the first dose of the AZD1222 COVID-19 vaccine. The findings were recently published in the journal Multiple Sclerosis and Related Disorders.

Their observations suggest that these relapses might be a rare adverse event of the adenoviral vector vaccine commercialized by AstraZeneca.

The 9 patients diagnosed with MS (n=8) or NMOSD (n=1) showed no evidence of disease activity for long periods (ie, 1-8 years) prior to inoculation. After being administered the first dose of the AZD1222 vaccine, patients relapsed within 7-25 days. Patients presented with increased disability and new lesions on magnetic resonance imaging (MRI).

Continue Reading

How the COVID-19 Pandemic Changed Attitudes in NMOSD Patients

“To the best of our knowledge, there have been no previous reports on the onset of MS and NMOSD relapses in close temporal association with AZD1222 vaccination in patients whose disease was otherwise well controlled. The very low number of cases reported here would qualify this adverse event, if indeed it is an adverse event, as extremely rare,” the researchers said.

Clinical trials on COVID-19 vaccines did not include patients with autoimmune disorders, such as MS or NMOSD. However, these patients are strongly encouraged to get their vaccines due to the urgency generated by the COVID-19 pandemic.

MS Treatment Reduces Efficacy of SARS-CoV-2 Vaccine

Patients should talk with their healthcare providers to clarify any issue and to help with vaccine hesitancy, the authors said. Also, there are particular recommendations for certain disease-modifying drugs that should be considered at the time of receiving the vaccine.


Fragoso YD, Gomes S, Gonçalves MVM, et al. New relapse of multiple sclerosis and neuromyelitis optica as a potential adverse event of AstraZeneca AZD1222 vaccination for COVID-19. Mult Scler Relat Disord. Published online October 13, 2021. doi:10.1016/j.msard.2021.103321