COVID-19 Vaccine Not Associated With Risk for New-Onset Myasthenia Gravis

The Pfizer-BioNTech mRNA vaccine for coronavirus disease 2019 (COVID-19) does not appear to increase the risk for new-onset myasthenia gravis (MG) or exacerbation of existing MG, according to a study published in the European Journal of Neurology.

Using data from the Clalit Health Services database and the Israeli Ministry of Health COVID-19 database, multivariable conditional logistic regression models found that the odds ratio (OR) for new-onset MG associated with receiving a COVID-19 vaccine within 4 weeks was 1.14. 

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A total of 332 new-onset patients with MG and 3,320 matched controls were identified for the study, however, only 40 (12%) of patients with MG and 370 (11%) of matched controls met the criteria of receiving a vaccine within 4 weeks prior to disease onset or index date, respectively. When the definition of exposure to the COVID-19 vaccine was expanded to 6 weeks or 8 weeks prior, the results were still similar (ORs 1.23 and 1.41).

In terms of MG exacerbations, multivariable models found an OR of 1.35 for patients who received a COVID-19 vaccine during the 4 weeks prior to the exacerbation.

A total of 62 patients with MG experienced exacerbations during the study period and COVID-19 vaccine administration was detected in 9 (14.5%) of the cases. This data was matched 248 randomly selected MG controls without exacerbation during the time period and 37 (14.9%) received a COVID-19 vaccine in the prior 4 weeks from the data point. Results were similar when the time period of prior vaccine administration was extended to 6 and 8 weeks (ORs 2.13 and 2.07; respectively). 

“In summary, this study suggests that mRNA Pfizer-BioNTech vaccine uptake is not associated with increased risk of either new-onset myasthenia gravis or myasthenia gravis exacerbation,” the authors said.

This article originally appeared on Rare Disease Advisor