New-Onset Systemic Lupus Erythematosus; This literature-non-study case was reported in a literature article and describes the occurrence of SYSTEMIC LUPUS ERYTHEMATOSUS (New-Onset Systemic Lupus Erythematosus) in a 27-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.      Family history included SLE. Concurrent medical conditions included Type 1 diabetes mellitus.    On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced SYSTEMIC LUPUS ERYTHEMATOSUS (New-Onset Systemic Lupus Erythematosus) (seriousness criterion medically significant). The patient was treated with PREDNISONE at a dose of low dose; HYDROXYCHLOROQUINE at an unspecified dose and frequency and MYCOPHENOLATE MOFETIL for Proteinuria, at an unspecified dose and frequency. At the time of the report, SYSTEMIC LUPUS ERYTHEMATOSUS (New-Onset Systemic Lupus Erythematosus) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Antinuclear antibody: positive (Positive) Positive, positive (Positive) Positive and positive (Positive) Positive. On an unknown date, Complement factor C4: low (Low) Low. On an unknown date, Double stranded DNA antibody: positive (Positive) Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered SYSTEMIC LUPUS ERYTHEMATOSUS (New-Onset Systemic Lupus Erythematosus) to be related.    Patient presented with symmetric inflammatory polyarthritis of the proximal interphalangeal joints, metacarpophalangeal joints, wrists, knees, and ankles two weeks after receiving the second dose of the SARS-CoV-2 mRNA-1273 vaccine.  Hydroxychloroquine was discontinued after she developed an urticarial rash.  Company comment:  This is a literature case concerning a 27-year-old female patient with a family history of SLE who experienced the serious (medically significant), unexpected event of systemic lupus erythematosus at an unknown time after the second dose of mRNA-1273 vaccine administration which was given on an unknown date, presumably before the event began. Testing was anti-nuclear antibodies and anti-DNA antibodies which were both positive and a decreased C4. Treatment was hydroxychloroquine which had to be stopped then mycophenolate mofetil. Events outcome was unknown at the time of this report. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Since the proprietary name of the suspect drug was not specified, the drug is handled as a Regulatory Authority product in this case report. The events were assessed as related to the product administration per partially available temporal association. Additional information is not expected.; Sender's Comments: This is a literature case concerning a 27-year-old female patient with a family history of SLE who experienced the serious (medically significant), unexpected event of systemic lupus erythematosus at an unknown time after the second dose of mRNA-1273 vaccine administration which was given on an unknown date, presumably before the event began. Testing was anti-nuclear antibodies and anti-DNA antibodies which were both positive and a decreased C4. Treatment was hydroxychloroquine which had to be stopped then mycophenolate mofetil. Events outcome was unknown at the time of this report. The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Since the proprietary name of the suspect drug was not specified, the drug is handled as a Regulatory Authority product in this case report. The events were assessed as related to the product administration per partially available temporal association. Additional information is not expected.