To study the COVID-19 vaccine three-dose safety and risk of COVID-19 in patients with myasthenia gravis

Various vaccines, including those against SARS-CoV-2, were reported to trigger or exacerbate myasthenia gravis (MG). As COVID-19 may potentially contribute to the tendency of MG patients to develop respiratory failure, it is important to study the safety of vaccines against SARS-CoV-2 and assess the risk of COVID-19 in MG patients. 

Among 215 MG patients treated in Tel Aviv Medical Center, 160 were interviewed about their response to the three-dose BNT162b2 mRNA vaccine. We assessed exacerbation rate and safety in a period of up to 6 weeks from each vaccine dose, as well as patient morbidity and mortality during COVID-19 compared to the general population. 

430 vaccine doses were administered across 150 patients. Thirteen patients (8.7%) complained of exacerbation within 6 weeks (risk period) of each vaccine dose, 8 (5.3%) confirmed by physician report. The exacerbation rates were similar during the risk period (5.6%) compared to corresponding period the previous year (4.8%). MG onset rates during the vaccination period were unaffected compared to previous years. Exacerbation rate among 15 patients who had COVID-19 was significantly higher (40%) compared to rate in the risk period following vaccination, with higher severe or lethal COVID-19 (26.7%) compared to the general population (0.96%), occurring in unvaccinated, steroid-treated, generalized MG patients.

Three-dose BNT162b2 vaccination is neither associated with exacerbation nor the new onset of MG, whereas COVID-19 is associated with severe disease and death in unvaccinated, steroid-treated generalized MG patients. Hence, it is strongly recommended for generalized MG patients to get vaccinated