Moderna COVID-19 Vaccine Seen as Safe and Effective With MG
The Moderna COVID-19 vaccine was safe and did not particularly worsen clinical symptoms in people with myasthenia gravis (MG), a Spanish study reported.
Patients developed a robust immune response after receiving the two recommended doses, despite being on immunosuppressive therapies. Additionally, no participant developed COVID-19 throughout the study.
The study, “Immune Response and Safety of SARS-CoV-2 mRNA-1273 Vaccine in Patients With Myasthenia Gravis,” was published in the journal Neurology: Neuroimmunology & Neuroinflammation.
In MG, the immune system mistakenly attacks proteins involved in nerve-muscle communication, primarily leading to muscle weakness. Muscles involved in breathing, as well as those of the eyes, face, arms, and legs, may be affected.
Infections, surgery, and certain medications are known triggers for disease exacerbations, or periods when symptoms become more severe. Since vaccines prompt an immune response in order to induce protection against a specific threat, some in the medical community are worried about the safety and effectiveness of vaccines developed against SARS-CoV-2 — the virus that causes COVID-19 — in patients on immunosuppressive treatments.
Researchers in Spain investigated the safety and efficacy of the Moderna COVID-19 (mRNA-1273) vaccine, which is based on a relatively new technology. mRNA vaccines provide cells with instructions to make a harmless piece of the SARS-CoV-2 spike protein. Traditional vaccines are made up of inactivated viruses, or viral proteins that trigger the body’s immune response.
Moderna vaccine responses
Their study was conducted from April to November 2021 during a vaccination campaign, with patients to receive the two recommended doses, administered 28 days apart.
Blood samples were collected before the first dose was administered and three months after the second vaccine dose.
Clinical changes were determined at the study’s start and at one week after the first and second doses, using the MG Activities of Daily Living (MG‐ADL) score — a patient-reported survey that assesses MG symptom severity. Changes in symptoms were only considered clinically relevant with an MG-ADL score increase of three points or more.
Of the 100 patients enrolled, 99 received both vaccine doses. A total of 83 people had generalized MG, a more severe and widespread form of the disease, and 17 had ocular MG — a disease form in which weakness is restricted to the muscles controlling eye and eyelid movements. The group’s mean disease duration was almost 12 years.
Although symptoms were considered to worsen after the first and second doses, increases in MG-ADL scores were less than two points. Therefore, these changes were not considered clinically relevant.
Blood was collected from a total of 98 participants. After vaccination, the majority of patients (88.8%) developed antibodies against the SARS-CoV-2 spike protein. All those not using a standard MG treatment, often immunosuppressive medications, developed a humoral immune response that is characterized by the production of antibodies. The humoral immune response was only slightly lower in immunosuppressed patients (86.7%).
Further analysis showed that patients on a combined therapy of prednisone and other immunosuppressives had an almost six times higher risk of not developing antibodies against the spike protein.
T-cell immune responses, which are considered important in providing a long-lasting immune response to COVID-19, were determined by measuring the levels of interferon gamma in the blood. Participants were grouped as having interferon gamma positive or interferon gamma negative results.
Of the 98 patients, 72 were interferon gamma positive (73.47%) and therefore showed a T-cell response after vaccination. Researchers also determined that “patients on combined immunosuppressive therapy had nearly [three] times more risk of not achieving a T-cell immune response after vaccination than patients on monotherapy.”
Side effects largely mild
Fourteen patients reported side effects after the first vaccine dose and 21 after the second dose. These were considered mild and included headaches, pain at the injection site, fatigue, fever, stomach pain or vomiting and diarrhea. No severe side effects were reported.
Patients who received both doses did not develop symptoms of COVID-19 in the following six months.
“Our results indicate that the mRNA-1273 vaccine does not cause significant [side effects] or relevant worsening in the clinical status of patients with MG. 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 team wrote.
“Taken together, these findings support the safety and efficacy of the mRNA-1273 vaccine in MG.”