Myasthenia gravis exacerbation; Right arm pain; Bowel incontinence; Bilateral knee pain; Moderna and Pfizer BioNTech vaccine; Moderna and Pfizer BioNTech vaccine; This spontaneous case was reported by a physician and describes the occurrence of MYASTHENIA GRAVIS (Myasthenia gravis exacerbation) in an elderly patient of an unknown gender who received mRNA-1273 (Spikevax) for COVID-19 immunization. The occurrence of additional non-serious events is detailed below.    Co-suspect products included non-company products ECULIZUMAB (SOLIRIS) solution for infusion for Myasthenia gravis and TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 immunization.    The patient's past medical history included Myasthenia gravis aggravated from 18-Nov-2016 to 09-Dec-2016, Hypercalcemia (Secondary) in October 2016, Bulbar palsy (Bulbar weakness), Ptosis, Osteoporosis, Cyst, Parathyroidectomy in October 2016, Plasmapheresis (with a total of seven exchanges for myasthenia gravis exacerbation.) and Immunoglobulin therapy (Immunoglobulin human normal treatment for myasthenia gravis exacerbation.). Previously administered products included for Immunization: Flu shot (Flu shot). Past adverse reactions to the above products included No adverse event with Flu shot. Concurrent medical conditions included Myasthenia gravis, Weakness generalized and Difficulty in standing (Could not stand without assistance). Concomitant products included AZATHIOPRINE (IMURAN [AZATHIOPRINE]) from 27-Nov-2019 to an unknown date, PYRIDOSTIGMINE BROMIDE (MESTINON), DEXAMETHASONE (DELTASONE [DEXAMETHASONE]) from 14-Dec-2021 to 29-Aug-2022, AMLODIPINE BESILATE (NORVASC) from 27-Nov-2019 to an unknown date, ACETYLSALICYLIC ACID (ASPIRIN E.C), ATORVASTATIN CALCIUM (LIPITOR) from 27-Nov-2019 to an unknown date, CALCIUM CARBONATE, COLECALCIFEROL (CALCIUM CARBONATE AND VITAMIN D), CHOLECALCIFEROL, ESCITALOPRAM OXALATE (LEXAPRO) from 27-Nov-2019 to an unknown date and LOSARTAN POTASSIUM (COZAAR) from 27-Nov-2019 to an unknown date for an unknown indication.   In July 2019, the patient started ECULIZUMAB (SOLIRIS) (unknown route) 10 mg/ml, Concentrate for solution for infusion. On an unknown date, the patient received dose of mRNA-1273 (Spikevax) (unknown route) 1 dosage form and dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) 1 dosage form. On an unknown date, the patient experienced MYASTHENIA GRAVIS (Myasthenia gravis exacerbation) (seriousness criterion medically significant), PAIN IN EXTREMITY (Right arm pain), ANAL INCONTINENCE (Bowel incontinence), ARTHRALGIA (Bilateral knee pain), INTERCHANGE OF VACCINE PRODUCTS (Moderna and Pfizer BioNTech vaccine) and COVID-19 IMMUNISATION (Moderna and Pfizer BioNTech vaccine). The patient was treated with Rehabilitation therapy for Myasthenia gravis. At the time of the report, MYASTHENIA GRAVIS (Myasthenia gravis exacerbation) was resolving, PAIN IN EXTREMITY (Right arm pain), ANAL INCONTINENCE (Bowel incontinence) and ARTHRALGIA (Bilateral knee pain) outcome was unknown and INTERCHANGE OF VACCINE PRODUCTS (Moderna and Pfizer BioNTech vaccine) and COVID-19 IMMUNISATION (Moderna and Pfizer BioNTech vaccine) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood creatinine: Creatinine was stable at 2.00. On an unknown date, Bone densitometry: Consistent with osteoporosis she had a significantly higher risk of fracture.. On an unknown date, Magnetic resonance imaging: A large lobulated cystic structure the right parietal lobe extending to the right occipital lobe suggestive of a benign cyst such as neuro-glial cyst..     The action taken with mRNA-1273 (Spikevax) (Unknown) was unknown.   For mRNA-1273 (Spikevax) (Unknown), the reporter considered MYASTHENIA GRAVIS (Myasthenia gravis exacerbation) and ANAL INCONTINENCE (Bowel incontinence) to be not related and PAIN IN EXTREMITY (Right arm pain) and ARTHRALGIA (Bilateral knee pain) to have an unknown relationship. No further causality assessments were provided for INTERCHANGE OF VACCINE PRODUCTS (Moderna and Pfizer BioNTech vaccine) and COVID-19 IMMUNISATION (Moderna and Pfizer BioNTech vaccine).    The patient's allergies were not reported. The patient had received immunoglobulin human normal treatment and also received plasmapheresis with a total of seven exchanges for myasthenia gravis exacerbation which occurred from 18-Nov-2016 to 09-Dec-2021.  On an unspecified date in Jul-2019, the patient had initiated treatment with Eculizumab (Soliris) for the treatment of generalized myasthenia gravis (gMG). The most recent dose administered prior to the onset of the event was not reported.   The patient had took the COVID-19 vaccine (Moderna and Pfizer booster). On 28-May-2019, the patient had myasthenia gravis exacerbation. The patient had dialysis on Monday Wednesday and Friday (MWF).The plasma exchange was carried out seven times for myasthenia gravis and was transferred to rehabilitation where she improved over three weeks. Corrective treatment for the other events was not reported.   It was reported events of myasthenia gravis and anal incontinence were not related to Eculizumab and the COVID-19 vaccine, the events were more likely due to the natural course of underlying MG and its manifestations. The causality for events pain in extremity and arthralgia was reported as Unknown for COVID-19 vaccine and not related to Eculizumab.  Company comment: This is a spontaneous case reported by a physician, concerning an elderly female patient, with relevant medical history of Myasthenia gravis, who experienced the unexpected and serious (due to medically significant) event of myasthenia gravis, which occurred unknown days after an unknown dose of mRNA-1273. Temporal association cannot be assessed due to lack of information on onset date of the events and vaccination date. It was noted revaccination with different COVID-19 vaccine and Interchange of vaccine products - vaccination with Pfizer and Moderna. MRI was performed with information about large lobulated cystic structure in right parietal lobe extending to the right occipital lobe suggestive of a benign cyst such as neuro-glial cyst, the bone density test was consistent with osteoporosis. The plasma exchange was carry out seven times and patient was transfer to rehabilitation where she improved. No further information disclosed about diagnostic tests performed or treatments received. Underlying medical condition could be a contributing factor in this case. At the time of the report, event was resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report. Events seriousness assessed as reported.; Sender's Comments: This is a spontaneous case reported by a physician, concerning an elderly female patient, with relevant medical history  of Myasthenia gravis, who experienced the unexpected and serious (due to medically significant) event of myasthenia gravis, which occurred unknown days after an unknown dose of mRNA-1273. Temporal association cannot be assessed due to lack of information on onset date of the events and vaccination date. It was noted revaccination with different COVID-19 vaccine and Interchange of vaccine products - vaccination with Pfizer and Moderna. MRI was performed with information about large lobulated cystic structure in right parietal lobe extending to the right occipital lobe suggestive of a benign cyst such as neuro-glial cyst, the bone density test was consistent with osteoporosis. The plasma exchange was carry out seven times and patient was transfer to rehabilitation where she improved. No further information disclosed about diagnostic tests performed or treatments received. Underlying medical condition could be a contributing factor in this case. At the time of the report, event was resolving. The benefit-risk relationship of mRNA-1273 is not affected by this report. Events seriousness assessed as reported.