Revaccination with different COVID-19 vaccine; Interchange of vaccine product; COVID-19; This spontaneous case was reported by a nurse and describes the occurrence of COVID-19 (COVID-19) in a 53-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 042L20A and 029A21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect products included non-company products TOZINAMERAN (COMIRNATY) for an unknown indication and TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for an unknown indication.    Concurrent medical conditions included MS. Concomitant products included OCRELIZUMAB for MS, DEXAMETHASONE for an unknown indication.   On 28-Jan-2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 02-Mar-2021, received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient received dose of TOZINAMERAN (COMIRNATY) (unknown route) at an unspecified dose and dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) at an unspecified dose. On 26-Sep-2021, the patient experienced COVID-19 (COVID-19) (seriousness criterion medically significant). On an unknown date, the patient experienced COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine product). At the time of the report, COVID-19 (COVID-19), COVID-19 IMMUNISATION (Revaccination with different COVID-19 vaccine) and INTERCHANGE OF VACCINE PRODUCTS (Interchange of vaccine product) outcome was unknown. Not Provided    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 26-Sep-2021, SARS-CoV-2 test: (Positive) Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in.  Caller mentioned, the patient had two MODERNA shots. He got convalescent ant body, the test he was near hospitalization, but the patient was able to use the antibody and help him out. He was an MS patient that gets an infusion (OCREVUS 30mg/ml) he gets that every 6 months. The problem being was he needs to get it 8 weeks prior to, he needs to get his Pfizer COVID booster either 8 prior to his infusion or 12 weeks after his infusion. He got convalescent ant body. The patient was very symptomatic and very weak and shortness of breath.  Company comment: This spontaneous case concerns a 53-year-old male patient, with relevant medical history of multiple sclerosis on Ocrelizumab every 6 months, and Dexamethasone, who experienced the unexpected serious (medically significant) AESI COVID-19. Patient received 2 doses of mRNA-1273 vaccine. Approximately 6 months after receiving the dose of mRNA-1273 vaccine, patient was diagnosed with COVID -19 confirmed by positive test, with symptoms of cough, shortness of breath and weakness. Convalescing antibodies was given for treatment. The outcome of event was unknown. Patient received 2 doses of mRNA-1273 vaccine at an interval of 33 days. History of multiple sclerosis could be considered as a risk factor and co-suspect Tozinameran vaccine as a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event assessed as serious based on medical judgement.   Most recent FOLLOW-UP information incorporated above includes: On 22-Dec-2021: Non Significant follow received contains no new information.; Sender's Comments: This spontaneous case concerns a 53-year-old male patient, with relevant medical history of multiple sclerosis on Ocrelizumab every 6 months, and Dexamethasone, who experienced the unexpected serious (medically significant) AESI COVID-19. Patient received 2 doses of mRNA-1273 vaccine. Approximately 6 months after receiving the dose of mRNA-1273 vaccine, patient was diagnosed with COVID -19 confirmed by positive test, with symptoms of cough, shortness of breath and weakness. Convalescing antibodies was given for treatment. The outcome of event was unknown. Patient received 2 doses of mRNA-1273 vaccine at an interval of 33 days. History of multiple sclerosis could be considered as a risk factor and co-suspect Tozinameran vaccine as a confounder. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event assessed as serious based on medical judgement.