In patients with well-controlled myasthenia gravis (MG), the 2-dose mRNA COVID-19 vaccines have been shown to be safe and well tolerated. These are the findings of a study published in the journal Muscle & Nerve.
Scant data are available on the safety of vaccination against SARS-CoV-2 infection in patients with MG, with these individuals — particularly those receiving immunosuppressive therapy — at high risk for COVID-19–associated complications. Although vaccines have demonstrated efficacy in reducing rates of infections and hospitalizations, many individuals with MG are concerned about the safety and effectiveness of vaccinations overall and about COVID-19 vaccines in particular —mainly due to the fear of side effects and exacerbations of myasthenic symptomatology.
For the study, researchers sought to explore the following: (1) reactogenicity (ie, a subset of reactions that happen soon after vaccination) and (2) whether individuals with MG experience an exacerbation after receiving an mRNA COVID-19 vaccination. They conducted a prospective, observational cohort study among a group of patients with MG who had been monitored at the outpatient neuromuscular clinic of a hospital located in Barcelona, Spain.
They recorded the dates of each patient’s first and second vaccinations, any local of systemic reactions, and exacerbation of MG symptoms and duration of the exacerbation compared with prevaccination baseline levels. All participants were followed from the day of vaccination through day 7 after each of the doses. Any adverse events that lasted for up to 72 hours were considered transient. The study period was from January 15, 2021 through September 1, 2021.
A total of 91 participants (36 men, 55 women) — with MG received COVID-19 vaccines. The mean patient age at the first vaccine dose was 58.8 years. Overall, 79.1% (72 of 91) of the participants were taking 1 or more immunosuppressants.
The most common adverse events included injection-site pain, fatigue, myalgia, chills, fever, and headache. Local and transient reactions were transient, with 58.2% of participants reporting 1 or more reaction(s). No serious adverse events and no anaphylactic reactions were reported. Patients aged older than 65 years reported significantly fewer adverse events than those aged younger than 65 years (45.2% vs 69.4%, respectively; 95% CI, 0.14-0.93; P =.32).
Although none of the participants experienced a myasthenic crisis, 2 developed a mild deterioration score on the Quantitative Myasthenia Gravis (QMG) scale compared with baseline values. Clinical outcome scores demonstrated no exacerbation of symptoms of MG.
Overall, “COVID-19 vaccination did not induce clinical exacerbation in stable patients with MG, regardless of their age, sex, history of myasthenic crisis, or whether they were taking immunosuppressant,” the researchers stated.
The researchers concluded that the “results suggest that mRNA COVID vaccines do not induce clinical exacerbations of MG, and have high levels of safety in stable patients with MG.”
Several limitations of the current study warrant mention. The sample size was relatively small. Only short-term reactivity was evaluated, whereas possible long-term negative effects of the vaccination were not monitored. Further, a lack of information exists with respect to patients with MG whose decision to be vaccinated or otherwise was supervised by their primary care physician.
Gamez J, Gamez A, Carmona F. Safety of mRNA COVID-19 vaccines in patients with well-controlled myasthenia gravis. Muscle Nerve. Published online August 11, 2022. doi:10.1002/mus