As we enter the third year of the pandemic, researchers and public health officials have much more data about the SARS-CoV-2 virus and its mutations, who is most vulnerable to them, and how people with underlying health conditions, including neurologic disorders like myasthenia gravis (MG), fare after an infection. With these data, we can provide better answers to the following questions about the risks of COVID-19 to people with MG, the safety of getting vaccinated and boosted, and how best to stay protected.

Am I at greater risk of contracting COVID-19 if I have MG?
“Most patients with MG are taking immunosuppressant drugs, which means they are at higher risk of getting infected with COVID-19 or having a more serious course of the disease,” says Alejandro Tobon, MD, FAAN, associate professor of neurology at the University of Texas Health Science Center in San Antonio. For example, people taking corticosteroids are estimated to have a 20 to 50 percent increased risk of becoming infected with COVID-19. And a Brazilian study published in Frontiers in Neurology in September 2020 of 15 adults with MG found that of those who were hospitalized for COVID-19, most had a severe course of the disease. Eighty-seven percent were admitted to the ICU, 73 percent needed mechanical ventilation, and at least 30 percent died.

Can COVID-19 make my MG symptoms worse?
Some case reports have suggested that COVID-19 can worsen some of the neurologic symptoms of MG, especially droopy eyelids (known as ptosis). Infection in general is also known to be a risk factor for myasthenic crisis, which involves worsening of muscle weakness that can lead to respiratory failure. Anyone experiencing an exacerbation of symptoms should test for COVID-19.

There have been a few anecdotal reports of people developing MG after a COVID-19 infection, but Dr. Tobon says there is no clear evidence that COVID-19 increases the risk of developing it. “It's very hard to prove causation, especially with a condition like MG that occurs in a relatively small population.”

Is it safe for me to get vaccinated if I have MG?
Two recent studies of people with MG who received the Pfizer or Moderna vaccine found that most had minor side effects such as pain and fever. In one published in the European Journal of Neurology in April 2022, about 7 percent of people reported some worsening of their MG symptoms after vaccination, but 90 percent said their symptoms did not worsen.

Another study published in Neuromuscular Disorders in March 2022 found that the most common side effects were pain, fatigue, and headache. Approximately 14 percent of patients reported increased weakness shortly after the injection, but most said that it did not persist. “For the vast majority of people with MG who experience any side effects associated with the COVID-19 vaccine, these resolve either on their own or with medication,” says Dr. Tobon.

Will getting vaccinated protect me if I have MG?
The short answer is yes. The longer answer is, it depends.

In initial studies of the mRNA vaccines produced by Pfizer and Moderna, which grouped people with all conditions that involve immunosuppression (either from the disease itself or medications patients might be taking), response to the vaccine was about 70 percent compared to about 90 percent for the general population.

“More recent studies suggest that effectiveness can be medication-specific,” says Dr. Tobon. “We have learned that mycophenolate mofetil (CellCept), rituximab (Rituxan), and steroids in general are associated with a poorer immune response to the vaccine.” Patients on these medications should discuss timing of treatments and vaccine doses with their doctors, says Dr. Tobon. Those starting mycophenolate mofetil, for instance, should wait two to four weeks after the second dose of the COVID-19 vaccine to begin treatment. (A 2021 report in Neurology provides a chart of recommendations for timing of vaccines in patients on common immunotherapies, including many drugs used to treat MG.)

Children ages 5 to 12 who are moderately or severely immunocompromised, including those with MG taking immunosuppressants, should receive three doses of an mRNA vaccine plus one booster. Those 12 years and older (including all adults) should get three shots of an mRNA vaccine and two boosters. Up-to-date guidance regarding vaccination can be found at cdc.gov. Visit vaccines.gov to locate the nearest vaccination site.

Are masks and social distancing still necessary?
Because of the continued spread of more contagious variants and because it is still not clear if vaccines are as effective in immunocompromised people as they are in others, people with MG, especially those taking immunosuppressants, should continue to take additional precautions. “People with MG should be extra careful about masking, avoiding crowded places, and social distancing—even among family members, because many people contract the infection from someone in their family,” says Dr. Tobon. “This is the best way—in addition to getting vaccinated and boosted—to minimize risk. You need to do what's necessary to protect yourself and your family.”