To investigate if the severity of MG predicts outcome of COVID-19 infection.

MG is a rare disease. The wide-spread nature and infectivity of SARS-CoV-2 mandate more understanding of the relationship between COVID-19 and MG.

This study is an observational retrospective multicenter study conducted at 7 neuromuscular centers inside the United States of America. Information about seropositive MG patients was collected. MG severity was assessed based on QOL15 questionnaire. The severity of COVID19 infection was based on admission to the ICU and/or death. Baseline characteristics of the participants were described based on the severity of COVID-19 infection and MG disease severity.

A total of 90 patients were included. MG severity was categorized into mild, moderate, or severe. The highest percentage of patients (49 patients) had mild COVID infection and MG. The frequency of low MG severity was similar in the low (73.33%) and high (66.67%) COIVD19 infection severity groups. COVID severity for patients being ever-vaccinated against COVID-19 showed an association with low severity COVID infection (p= 0.003). There was no significant association between MG disease severity (p= 0.569), MG weakness type (p= 0.199), high dose intake of MG medication (p= 0.475) and COVID-19 infection severity even after controlling possible confounders.

No association between MG severity and COVID-19 severity was found. However, we suspect the relationship between both diseases, if any, to be complex and multifactorial.