COVID-19 vaccination is safe for patients with myasthenia gravis (MG) patients and is not associated with worsening disease severity or a higher prevalence of adverse effects compared to the general population, according to a study recently published in Muscle & Nerve.

“There is no information available regarding the safety of the COVID-19 vaccines in MG patients including the risk of vaccine-associated disease exacerbations,” the authors wrote, in explaining the reason for their study. 

Due to the theoretical concern of MG flare-ups following COVID-19 vaccination, this retrospective chart review aimed to use validated clinical questionnaires such as the virtual Myasthenia Gravis Impairment Index (vMGII), Single Simple Question (SSQ), and Patient Acceptable Symptom State (PASS) to assess worsening of the disease after vaccination.

The study included 200 patients from the Prosserman Family Neuromuscular Clinic at Toronto General Hospital, Ontario, Canada, who received 2 doses of any available COVID-19 vaccine between February and August 2021.

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Patients with congenital MG were excluded. In the studied population, 73% received the Pfizer-BioNTech COVID-19 vaccine, 12% the Moderna COVID-29 vaccine, and 6% the Oxford-AstraZeneca COVID-19 vaccine.  

All patients were interrogated by phone before the first dose and 2 weeks after each dose. In every case, the vMGII, SSQ, and PASS were done. Local and systemic adverse effects not related to MG severity were also asked about.

At the end of the study, no significant vMGII, SSQ, or PASS differences from before to after vaccination were observed. The majority of the studied population was well controlled, as indicated by a mean SSQ mean value of over 80% and a mean vMGII of 7-8. 

There were no hospital visits during the duration of the study. After vaccination, the incidence of adverse effects such as fatigue and injection site pain was similar to that of the general population. 

“This study provides evidence that a two-dose regimen of any of the available COVID-19 vaccines is safe without worsening MG status, and with adverse reactions similar to those in the general population,” the authors wrote. 

People with MG are at higher risk of severe COVID-19 infection because of their immunosuppressive treatment, so the authors strongly recommend COVID-19 vaccination in these patients.


Pincheira AU, Alnajjar S, Katzberg H, et al. Retrospective study on the safety of COVID-19 vaccination in myasthenia gravis. Muscle Nerve. Published online June 8, 2022. doi:10.1002/mus.27657