Blood clot; COVID-19; knee replacement; This spontaneous case was reported by a consumer and describes the occurrence of THROMBOSIS (Blood clot) in a 68-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product MEPOLIZUMAB (NUCALA) injection for Eosinophilic asthma.    Concurrent medical conditions included Wheezing. Concomitant products included ALBUTEROL [SALBUTAMOL], FLUTICASONE FUROATE, UMECLIDINIUM BROMIDE, VILANTEROL TRIFENATATE (TRELEGY), MONTELUKAST, AZELASTINE, MOMETASONE FUROATE (FLONASE [MOMETASONE FUROATE]), TRIAMCINOLONE ACETONIDE (NASACORT) and OMEPRAZOLE for an unknown indication.   In 2019, the patient started MEPOLIZUMAB (NUCALA) (Subcutaneous) 100 milligram every four weeks. On an unknown date, the patient received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form, second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form and first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In March 2021, the patient experienced KNEE ARTHROPLASTY (knee replacement). On an unknown date, the patient experienced THROMBOSIS (Blood clot) (seriousness criterion medically significant) and COVID-19 (COVID-19). The patient was treated with RIVAROXABAN (XARELTO) from April 2021 to April 2022 at an unspecified dose and frequency and NIRMATRELVIR, RITONAVIR (PAXLOVID) at an unspecified dose and frequency. At the time of the report, THROMBOSIS (Blood clot) and KNEE ARTHROPLASTY (knee replacement) had resolved and COVID-19 (COVID-19) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2019, Eosinophil count: 675. On 08-Aug-2022, SARS-CoV-2 test: (Positive) positive with no symptoms other than scratchy throat. On 12-Aug-2022, SARS-CoV-2 test: (Negative) negative. On 17-Aug-2022, SARS-CoV-2 test: (Positive) She tested positive again and was sick for one week with cough and exhaustion. On an unknown date, Eosinophil count: 62. On an unknown date, Weight: lost 2 lb and gained 8 lb.         The patient always had a wheeze no matter what she was on. In 2019 (prior to starting Nucala) absolute eosinophils were 675. Prior to Nucala asthma was mostly well managed, in her case she never felt completely free of wheezing but it was manageable. She swam every other day, life got on and she could do what she wanted to do. With Nucala she did not feel 100 percent different because it was mostly managed before but her numbers had dropped down radically. Last blood draw absolute eosinophils were 62. The hope with Nucala was to eventually get off the inhaler but at that point her pulmonologist was not comfortable with that. She has not had a fare requiring steroids that she could recall, or respiratory distress since starting treatment with Nucala. She had a knee replacement 18 months ago, which on treatment with Nucala, she would be having orthoscopic surgery to clean up the scar tissue from that surgery, in Nov-2022 because she could no longer pivot her knee. After surgery she had 2 blood clots in calf and PE. Testing revealed factor 5 leiden mutation resulted in predisposition to blood clots. In Aug-2022, she went on 9 day cruise. She was treated with Paxlovid and tested negative for COVID-19 on 12-Aug-2022. Doctor prescribed unspecified antibiotics and cough medicine. Sometimes she would go 5 weeks between doses due to travel but never missed a dose. She just got back from vacation in where she enjoyed time eating and relaxing. She gained 8 lb but had since lost 2 lb.  Company Comment: This is a spontaneous case concerning  a  68-year-old, female patient with no relevant medical history, who experienced the unexpected serious (medically significant) event of (AESI) Thrombosis and unexpected non-serious events of Knee arthroplasty and Additional event of Covid-19. The exact date of administration of first dose of mRNA-1273 and onset of the events was not specified, hence latency could not be assessed. Patient tested positive for SARS COV-2 (twice), slightly elevated eosinophil count. The patient always had a wheeze. Prior to Nucala asthma was mostly well managed, in her case she never felt completely free of wheezing but it was manageable. With Nucala she did not feel 100 percent different because it was mostly managed before but her numbers had dropped down radically. Last blood draw absolute eosinophils were 62. The hope with Nucala was to eventually get off the inhaler but at that point her pulmonologist was not comfortable with that. She has not had a fare requiring steroids that she could recall, or respiratory distress since starting treatment with Nucala. She had a knee replacement 18 months ago, she could no longer pivot her knee. After surgery she had 2 blood clots in calf and PE. Testing revealed factor 5 leiden mutation resulted in predisposition to blood clots. Patient was treated with Paxlovid and tested negative for COVID-19. Doctor prescribed unspecified antibiotics and cough medicine. Sometimes she would go 5 weeks between doses due to travel but never missed a dose. She just got back from vacation in where she enjoyed time eating and relaxing. She gained 8 lb but had since lost 2 lbs.The benefit-risk relationship of mRNA-1273 Vaccine, is not affected by this report. Sender's Comments: This is a spontaneous case concerning  a  68-year-old, female patient with no relevant medical history, who experienced the unexpected serious (medically significant) event of (AESI) Thrombosis and unexpected non-serious events of Knee arthroplasty and Additional event of Covid-19. The exact date of administration of first dose of mRNA-1273 and onset of the events was not specified, hence latency could not be assessed. Patient tested positive for SARS COV-2 (twice), slightly elevated eosinophil count. The patient always had a wheeze. Prior to Nucala asthma was mostly well managed, in her case she never felt completely free of wheezing but it was manageable. With Nucala she did not feel 100 percent different because it was mostly managed before but her numbers had dropped down radically. Last blood draw absolute eosinophils were 62. The hope with Nucala was to eventually get off the inhaler but at that point her pulmonologist was not comfortable with that. She has not had a fare requiring steroids that she could recall, or respiratory distress since starting treatment with Nucala. She had a knee replacement 18 months ago, she could no longer pivot her knee. After surgery she had 2 blood clots in calf and PE. Testing revealed factor 5 leiden mutation resulted in predisposition to blood clots. Patient was treated with Paxlovid and tested negative for COVID-19. Doctor prescribed unspecified antibiotics and cough medicine. Sometimes she would go 5 weeks between doses due to travel but never missed a dose. She just got back from vacation in where she enjoyed time eating and relaxing. She gained 8 lb but had since lost 2 lbs.The benefit-risk relationship of mRNA-1273 Vaccine, is not affected by this report.