Tetanus Vaccine Does Not Trigger MG Exacerbations, European Study Shows

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by Alice Melão |

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Vaccination for protection against tetanus is safe and does not aggravate any clinical or immunological features of myasthenia gravis, according to the results of a report published in the journal Vaccine.

Myasthenia gravis is an autoimmune disorder caused by the abnormal production of antibodies that attack one’s body. These autoantibodies target the acetylcholine receptor (AChR) and, less frequently, the muscle-specific kinase (MuSK).

To manage the symptoms of myasthenia gravis (MG), patients usually receive immunosuppressive therapies. Although they can be beneficial by reducing the production and effects of autoantibodies, they also reduce the normal protective function of the immune system. This makes the patients more exposed to opportunistic infections, which can worsen the disease symptoms.

Use of vaccinations to prevent infections is common among the general population, but the effect they may have on individuals with autoimmune diseases is still debatable.

Previous studies have demonstrated that the common flu vaccine is safe and its benefits outweigh the risks in people with MG. Still, little is known about the effects of other vaccines in patients with myasthenia gravis.

In the study “A prospective, placebo controlled study on the humoral immune response to and safety of tetanus revaccination in myasthenia gravis” a research team at Leiden University Medical Centre in the Netherlands conducted a Phase 4 study (EudraCT Number: 2014-004344-35) evaluating the effects of tetanus vaccination in patients with myasthenia gravis.

The team selected the tetanus toxoid vaccine because it is a frequently administered vaccine and it has a good safety and immune response profile in healthy individuals, as well as in immuno-compromised patients.

The study included 57 patients with myasthenia gravis, nine patients with Lambert-Eaton myasthenic syndrome (LEMS), and 20 healthy individuals, who were re-vaccinated with tetanus toxoid. In addition, 23 myasthenia gravis patients were included in the study and were injected with a placebo.

Evaluation of the patients’ immune response four weeks after vaccination showed that 60 of them had a significant increase of the anti-tetanus antibody, which is the expected effect of the vaccine. The patients who received immunosuppressive therapy showed lower levels of anti-tetanus antibody; however, the overall immune response to the vaccine was still positive.

Researchers confirmed the vaccine did not cause any exacerbation of myasthenia gravis or LEMS symptoms, which was confirmed by the unchanged levels of autoantibodies before and after the shot.

Overall the team concluded that “a tetanus revaccination in patients with myasthenia gravis or Lambert-Eaton myasthenic syndrome is safe and induces a significant immune response, irrespectively of their immunosuppressive medication.”