Researchers from Italy reported 3 cases of new-onset myasthenia gravis after SARS-CoV-2 mRNA vaccination in a report they published in Neurological Sciences. Clinicians should be aware of possible new-onset myasthenia gravis, the authors of the report said, “especially with the current recommendation of booster doses.”

The cases presented here are that of 3 men who presented with ocular and bulbar symptoms following the SARS-CoV-2 vaccine. All had high levels of AChR antibodies in their serum.

The first patient was a man, aged 90 years who had chronic ischemic heart disease and chronic kidney disease. He developed symptoms of myasthenia gravis 10 days after the second dose of the BNT162b2 vaccine. He was treated with 30 mg of pyridostigmine 3 times a day, which was sufficient to control his symptoms and no further immunosuppressive treatment was given due to his age.

The second patient was aged 80 years and had hypertension, type 2 diabetes mellitus, and hypercholesterolemia. He developed symptoms 6 days after the second dose of the mRNA-1273 vaccine. He was treated with 30 mg of pyridostigmine 3 times a day and 25 mg of prednisone once a day but his condition continued to worsen. He was then treated with 5 plasma exchange sessions, which led to a clinical improvement.

Read more about myasthenia gravis epidemiology

Finally, the third patient was aged 55 years and had hypertension and chronic tension-type headache. His symptoms started 3 days after the first dose of the mRNA-1273 vaccine. He was given 60 mg of pyridostigmine 4 times a day and a 5-day course of intravenous immunoglobulin, which improved his clinical condition.

The researchers speculated that myasthenia gravis could have developed as a result of the hyperstimulation of the innate immune system. Alternatively, symptoms could have been the result of pre-existing subclinical disease, they said. 

A SARS-CoV-2 infection itself can lead to the development of autoimmune diseases and cases of myasthenia gravis associated with COVID-19 have been described.

Reference

Fanella G, Baiata C, Candeloro E, et al. New-onset myasthenia gravis after mRNA SARS-CoV-2 vaccination: a case series. Neurol Sci. Published online July 23, 2022. doi:10.1007/s10072-022-06284-5