In patients with myasthenia gravis (MG), mRNA vaccination against SARS-CoV-2 infection is safe and has demonstrated no negative effect on disease course, according to study findings published in Neurology: Neuroimmunology & Neuroinflammation.

The researchers sought to establish whether the mRNA-1273 vaccine is safe, and has the ability to induce humoral and cellular responses in patients with MG. They also took into consideration that several immunosuppressive and immunomodulatory agents are commonly utilized for the treatment of patients with the disease. MG, which is known to be a rare neuromuscular disorder that is caused by autoantibodies against postsynaptic receptors in the neuromuscular junction, is associated with muscular weakness.

In the observational, longitudinal, prospective study conducted in Spain, researchers recruited a total of 100 unvaccinated patients with MG who were scheduled to receive a SARS-CoV-2 vaccination between April 2021 and May 2021. All of the study participants received 2 doses of the vaccine, which were separated by a period of 28 days.


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Blood samples were obtained in serum and heparin tubes at the baseline visit prior to the first vaccine dose and at 90 days following administration of the second vaccination. Immunoglobulin G (IgG) positivity against nucleocapsid protein (NP) was detected in baseline blood samples with the use of the SARS-CoV-2 NP-IgG enzyme-linked immunosorbent assay (ELISA) kit. A high-sensitive SARS-CoV-2 S1-IgG ELISA kit was used to detect spike-IgG in the 90 days following vaccination. A sample was considered positive if values were ≥5 IU/mL. The cellular immune response was assessed with the use of an interferon-gamma release assay (IGRA).

The primary outcomes included clinically significant changes in MG symptoms following vaccination, adverse events (AEs), and seroconversion and T-cell immune response rates.

Clinical changes during the study were evaluated via the use of the validated Myasthenia Gravis Activities of Daily Living (MG-ADL) score, which was administered through a telephone call. The MG-ADL score was obtained at 3 time points, as follows: (1) MG symptoms that occurred in the 7 days prior to the baseline visit; (2) MG symptoms that occurred in the 7 days following the first vaccine administration; and (3) MG symptoms that occurred in the 7 days after the second vaccine administration. Symptoms were considered “clinically relevant” when an increase in MG-ADL score of 3 points or more was observed.

Among a total of 99 individuals who completed the full vaccination schedule, 98 had 2 blood samples obtained. A statistically worsening of symptoms was revealed following the first and second doses of the mRNA-1273 vaccine, but it was not considered clinically relevant. Further, mild AEs were reported in 14 participants after the initial vaccination and in 21 participants following the second vaccine dose.

A total of 87 patients developed a humoral response and 72 patients demonstrated a T-cell response following vaccination. Combined treatment with prednisone and other immunosuppressive agents was associated with a significantly lower seroconversion ratio (odds ratio [OR], 5.97; 95% CI, 1.46-24.09; P = .015) and a lower T-cell response ratio (OR, 2.83; 95% CI, 1.13-7.13; P =.024).

A major limitation of the study was the lack of a proportional control group. The cohort evaluated, however, comprised a group of individuals with MG who were not receiving immunosuppressive therapy, who had a 100% rate of seroconversion, and who achieved a 93% T-cell response, as measured by IGRA.

The researchers concluded that “Despite receiving immunosuppressive therapy, the patients in this study achieved significant humoral and cellular immune responses, and none of those who completed the vaccination scheme developed COVID-19 during a period of high incidence.”

The current study findings thus support the safety and efficacy of the mRNA-1273 vaccine in patients with MG.

Disclosure: None of the study authors has declared affiliations with biotech, pharmaceutical, and/or device companies.  

Reference 

Reyes-Leiva D, López-Contreras J, Moga E, et al. Immune response and safety of SARS-CoV-2 mRNA-1273 vaccine in patients with myasthenia gravis. Neurol Neuroimmunol Neuroinflamm. Published online June 20, 2022. doi:10.1212/NXI.0000000000200002

This article originally appeared on Neurology Advisor