Evaluation of Clinical Effects of COVID-19 Infection and Vaccines on Myasthenia Gravis

Introduction: In this study, we aimed to investigate the clinical effects of COVID-19 infection and vaccines on Myasthenia gravis (MG) during the pandemic. Methods: A total of 141 MG patients between April 2020 and December 2021 were retrospectively analyzed. Data including demographic and clinical characteristics of patients, COVID-19 test results, and vaccine types (mRNA-BNT162b2 and/or inactivated-CoronaVac) were recorded. All patients were followed by face-to-face interviews and/or phone calls. Worsening MG symptoms after COVID-19 infection or vaccines were noted. Results: A total of 60 patients were diagnosed with COVID-19, and reverse transcriptase-polymerase chain reaction test results were COVID-19 positive in 54 (90%) patients. Twenty-eight (46.7%) patients had lung involvement, while 20(33.3%) patients were followed in the ward. Twelve (20%) patients were followed in the intensive care unit, and two of them (3.3%) died. Both deceased patients were unvaccinated. The most common symptoms were fatigue (78.3%), and 13(21.7%) patients were asymptomatic. Of the patients, 96(68%) received at least one dose BNT162b2 or CoronaVac, while 30.4% of the patients received >= 3 doses of vaccines. The local skin irritation and fatigue rate was significantly higher with BNT162b2 vaccine than CoronaVac (p<0.001 and p=0.004, respectively). No serious side effect was observed with either vaccine. Five patients had worsening MG symptoms after vaccination during a six-week follow-up. None of the patients experienced myasthenic crises. Conclusion: Our study results suggest that COVID-19 infection affects MG similar to the general population and does not lead to worsening MG symptoms. Both mRNA and inactivated vaccines with proven efficacy can be used safely in MG patients.