Multiple Sclerosis; sick for a day; blood pressure was 150/83; This spontaneous case was reported by a patient and describes the occurrence of MULTIPLE SCLEROSIS (Multiple Sclerosis) in a 66-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 039B21A and 032M20A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     No allergies were reported.  Concurrent medical conditions included Multiple sclerosis (Had symptoms of Multiple Sclerosis before receiving the vaccination but was diagnosed in May 2022.).   On 17-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 17-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. In April 2021, the patient experienced ILLNESS (sick for a day). In 2021, the patient experienced BLOOD PRESSURE INCREASED (blood pressure was 150/83). In May 2022, the patient experienced MULTIPLE SCLEROSIS (Multiple Sclerosis) (seriousness criterion medically significant). At the time of the report, MULTIPLE SCLEROSIS (Multiple Sclerosis), ILLNESS (sick for a day) and BLOOD PRESSURE INCREASED (blood pressure was 150/83) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, Blood pressure measurement: 150/83. On an unknown date, Blood pressure measurement: 110/70.         Patient would like to know if they can still get the booster since their last shot was in April 2021. Patient would like to know the efficacy of the booster doses. Patient would like to know why is the booster dose lower than/half the dose of the shots from the primary series  Concomitant and Treatment product use was not provided by the reporter.  Reported that patient was sick for a day after the second vaccination. Patient had symptoms of Multiple Sclerosis before receiving the vaccination but was diagnosed in May 2022. Patient was not tested or diagnosed covid positive.  Company comment: This is a spontaneous case concerning a 66-year-old-female patient with medical history of symptoms of multiple sclerosis before receiving vaccination, who was diagnosed with the serious (medically significant) unexpected AESI multiple sclerosis, more than a year after receiving the second dose of mRNA-1273. Clinical course, diagnostic tests and treatment details were not provided. Reported symptoms of multiple sclerosis before vaccination remains as a confounder for the event. Further information had been requested. The benefit-risk relationship of mRNA-1273 is not affected by this report.; Sender's Comments: Company comment: This is a spontaneous case concerning a 66-year-old-female patient with medical history of symptoms of multiple sclerosis before receiving vaccination, who was diagnosed with the serious (medically significant) unexpected AESI multiple sclerosis, more than a year after receiving the second dose of mRNA-1273. Clinical course, diagnostic tests and treatment details were not provided. Reported symptoms of multiple sclerosis before vaccination remains as a confounder for the event. Further information had been requested. The benefit-risk relationship of mRNA-1273 is not affected by this report.